water transparency

c,. SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME. 139,. NUMBER. 10. WATER TRANSPARENCY OBSERVATIONS ALONG THE EAST COAST OF NORTH AMERICA (With. 2 Plates). By. JEROME WILLIAMS FENIMORE JOHNSON. E. R.. AND. ALBERT. C.. DYER. (Publication 4391). CITY OF. WASHINGTON. PUBLISHED BY THE SMITHSONIAN INSTITUTION OCTOBER 26, 1960.



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOLUME 139, NUMBER 10. WATER TRANSPARENCY OBSERVATIONS ALONG THE EAST COAST OF NORTH AMERICA (With. 2 Plates). By E.. JEROME WILLIAMS R. FENIMORE JOHNSON AND. ALBERT. C.. DYER. •&&££*$. %£&&*. sw. \t«. (Publication 4391). CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION OCTOBER 26, 1960.

THE LORD BALTIMORE PRESS, BALTIMORE, MD.,. U.. S.. A.. INC..

WATER TRANSPARENCY OBSERVATIONS ALONG THE EAST COAST OF NORTH AMERICA By. JEROME WILLIAMS, E. R. FENIMORE JOHNSON AND ALBERT C. DYER * (With. 2 Plates). INTRODUCTION Marine. biologists. have long been interested in the transparency of. natural waters as an important parameter in the determination of. both the amount and type of plant this interest,. 22, 23],. 2. many. life at. various depths.. transparency surveys, in the oceans. in lakes [7, 33],. Owing. to. [4, 8, 16, 19,. and on pure water [27], have been made.. In recent years, however, this interest in water clarity has spread to other. fields,. television.. such as underwater photography (1, 9, 20, 24, 33) and is a growing movement among workers. In addition, there. in the field to utilize transparency as a "tag" for. water masses in the. study of such things as circulation patterns [23, 25]. During the years 1947-51 the yacht Elsie Fenimore. made a. rather. extensive survey of water transparency conditions along the east coast. America from Labrador to the Gulf of Mexico, including some stations around Newfoundland and the British West Indies. Even though the data herein presented are admittedly far from complete and a number of other studies have been made of the area [3, 5, 10, 11, 12, 13, 14, 15, 17, 18, 21, 28, 31] this study represents, from a geographical standpoint, the most extensive single piece of work done on the subject to date. For this reason, if for no other, it seems desirable to publish this information in the present form so that it may become available. To make the data as universal as possible the unit chosen was the of North. so-called Equivalent Secchi Disc Reading.. Since. it. is. obviously im-. measurement of water transparency if the water mass to be measured is at a great depth, this water mass is hypothetically brought to the surface for measurement. Thus the Equivalent Secchi Disc Reading may be said to be the dispossible to use the Secchi Disc [32] for. 1. Mr. Williams. is. associated with the Chesapeake. Bay. Institute. ;. Mr. Johnson. a research associate in the Limnology Department, Academy of Natural Sciences of Philadelphia; and Mr. Dyer is connected with the Fenjohn Company.. is. 2. Numbers. in brackets indicate references in the bibliography.. SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL.. 139,. NO. 10.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 2. tance at which a Secchi Disc would just disappear in. water and. As an. if. were. that water. example,. if it. VOL. I39. were immersed. at the surface.. an Equivalent Secchi Disc Reading were given. if. would mean that if mass at a depth of 100 feet were brought to the surface a Secchi Disc would disappear from view at a distance of 10 feet in this transposed volume of water.. as 10 feet for water at a depth of 100 feet, this. the water. The. Secchi Disc. parency, since. it. is. was. admittedly a crude indicator of water trans-. by marine biologists to measure This is a measure of the amount. originally used. the so-called extinction coefficient.. of light reaching a horizontal surface at some depth. the extinction coefficient. is. ency but also a function of such things as sea altitude of sun,. reading it. is. and other. Unfortunately,. not only a measure of the water transpar-. factors.. Even. so,. state,. probably a reasonably good indicator of water clarity. taken with the sun fairly high in the sky and. is. cloud cover,. however, the Secchi Disc if. it. is. if. viewed. through a glass-bottom viewer or hydroscope [30] In addition, the Secchi Disc reading is an easily understood unit, generating an intuitive feeling for the existing conditions, so that it. has become fairly universal in. its. use as an indicator of water. transparency.. Of. course, the actual Secchi Disc reading gives an average value. of the transparency of the surface layers, so that edly different water exists. For. be seen.. somewhere from top. this reason, other. if. a layer of mark-. to bottom,. it. will not. instruments which measure trans-. parency of relatively small volumes of water were used. in conjunction. These will be discussed in a later section. The writers wish to express their appreciation to Dr. Ruth Patrick, Curator, and Miss Margaret Le Mesurier, Librarian, of the Department of Limnology, Academy of Natural Sciences of Philadelphia, for. with the. disc.. Ap-. their indispensable aid in the preparation of this manuscript.. preciation. is. also expressed to the Smithsonian Institution for material. aid and advice in this project and publication of the paper,. Academy. of Natural Sciences of Philadelphia for. its. and. to the. contribution of. personnel and materials in the carrying out of this program.. We. regret that space does not permit the listing of over 50 other persons. and. institutions to. whom we. are indebted for advice and assistance. rendered.. INSTRUMENTS The instruments. utilized in the. accumulation of the data presented. herein can roughly be divided into two classes. :. ( 1 ). those that meas-.

WATER TRANSPARENCY. NO. 10. ure the. instruments in. JOHNSON, DYER. 3. environment and (2) laboratory-type which a water sample is removed from the medium. medium. and examined. — WILLIAMS,. in its natural. shipboard laboratory.. in the. The. first. type. is. usually. considered the more reliable when dealing with natural waters, since the transparency properties seem to change rather markedly when a. sample is. is. taken out of. discussed. its. natural environment, and therefore this type. first.. I.. IN SITU INSTRUMENTS. A. Secchi Disc. (pi. 1, fig. 4). owing to its ruggedness and ease of use, was the most often used of any of the devices to be listed. The disc used was j\ inches in diameter and was painted a flat white, having a reflectance coefficient of about 0.8. It was obtained from the Oceano-. The Secchi. Disc,. graphic Institution at. Woods. A. specially designed hydro-. scope. was occasionally used. in conjunction with the. (pi.. 1,. fig.. 3). Hole, Mass.. Secchi Disc to eliminate water-surface effects. Generally the Secchi Disc was observed by means of a glass-bottom bucket. Readings were the sunny side of the ship, except where otherwise noted tables, and the recorded value is the distance from the data in the hydroscope to the disc, i.e., the distance traveled by the the bottom of. made from. reflected light is. from the. disc surface. through the medium in which. it. suspended. B.. Point Source Light. a number of occasions the transparency of water was measured by observing the distance at which a point source of light can be seen. This method of measurement may be seen to be similar to that of the. On. Secchi Disc.. Although a true point source of. light is well-nigh physically. impos-. approximated sible, the tungsten filament of a 1,000-watt diver's lamp in the encountered transparency this well enough for the range of near coastal and inland waters. ultraclear sections of the. It. unfortunately. open ocean, where. it. fails. badly in the. diminishes in size and. eludes the observer before reaching extinction through absorption. In turbid waters the point source shows up as an incandescent spot. surrounded by scattered light having the appearance of luminescence into the in which the visual range is the point at which it disappears hand, other the on water, clearer In light. background of scattered can be seen at all, is seen only and disappears while observer close to the. the background of scattered light,. when. the point source. is. if it.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 4. the incandescent spot. spot. is still. VOL. 139. The energy from. plainly visible.. this. so reduced by attenuation that the structural shape of the. is. The. filament can be clearly seen.. visual range is then taken to be the. distance to that point at which the filament completely disappears.. Most of these observations were made horizontally with the lamp and the objective of the hydroscope both placed 5 feet below the water surface. For the sake of completeness, observations were made both during the day and at night. Plate 1, figure I, shows the point source of light being observed through the hydroscope. C.. Illuminated Letter. This observation method involved the use of a low-powered lamp enclosed in a small housing with an opal glass window, in front of. which was mounted a rotatable disc which had a series of cutout letters. The whole rig was mounted on a pole which could be extended approximately 5 feet below the surface and was observed by means of. The procedure adopted consisted of bringing the illutoward the hydroscope in a horizontal direction until. the hydroscope.. minated. letter. the observer could. make. a positive identification of the nature of the. letter.. D.. To. Underwater Objects. some idea of the horizontal visibility available at various and white balls approximately 6 inches in diameter were lowered about 5 feet below the surface of the water and observed with the hydroscope. The horizontal distance at which the balls disappeared from view was recorded. obtain. stations, black. E.. To. Navy Hydrophotometer Mk.. II (pi.. 2). 1, fig.. obtain a measure of the variation in transparency with depth,. standard U.S.. They. U.S.. Navy hydrophotometers were used. quite extensively.. two principal parts; a control box and an underwater unit connected by an electrical cable. The underwater unit may be lowered to any desired depth and the transparency at that depth is. consisted of. indicated at the control box.. a number of earlier instruments. The underwater. It is. very similar in. [6, 29,. unit consists of. operation to. its. 33].. two heads separated by a fixed Plf and the source and another photocell, P 2. distance of 0.5 meter, one head containing a photocell,. other containing a collimated light. which cell. P. is 1. .. connected so that. its. output. is in. opposition to the output of. In operation the light shines both on. P. x. and. P. 2. and the com-.

WATER TRANSPARENCY. NO. IO. — WILLIAMS,. JOHNSON, DYER. 5. adjusted by means of light irises so that box reads ioo percent when the underwater assumed to be a nonattenuating medium). Then,. bined output of the two. cells is. the meter in the control unit. is. in air (air is. as an attenuating. and photocell. P. lt. medium such. is. placed between the light. some. fraction of ioo percent.. as water. the meter will read. a light loss of about 4 percent per glass-air interface owing to the different indices of refraction of glass and air. Actually, since there. is. which does not occur when the device is submerged because of the similarity of glass and water indices of refraction, the reading in air should be set to 92 percent instead of 100 percent [34].. There. is. a definite temperature effect on the device, but in view of. measurement and the length of time required for an internal temperature change to occur, it is felt that this temperature dependence is negligible. This temperature effect is reported in the National Bureau of Standards. the sources of error existent in the other methods of. Text No. 43P-1/47. F.. This instrument field. is. Hydroscope. essentially an. underwater telescope having a 15. of view with interchangeable heads for either vertical or hori-. zontal viewing for Secchi Disc or other visibility range readings.. Plate. 1,. shows the device which. figure 3,. is. approximately 15 feet The viewing head. long and uses a lens system of unit magnification. is. equipped with a focusing eyepiece, a rubber face pad to exclude. external light, and two positioning control handles.. In use, the hydroscope. is. supported in a ball-and-socket mount on. a platform extending from the side of the ship, with the objective. head of the instrument extending 5 feet below the water surface. II.. LABORATORY TYPE INSTRUMENTS A. Peraqnamcter. This device. is. (pi. 2, fig. 1). very similar in principle to the illuminated. described above, except that the letter to be identified. is. letter. placed in a. with the water of interest by means of a pump. The observer looks into this tube and is able to move the image of the letter, by means of a movable mirror, until long tube (11 feet long) which. is filled. positive identification is possible.. The peraquameter was used when nated. letter,. was found. to be. under 22. visual range, using the illumifeet..

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 6. B.. To measure. Scattering Meter (pi.. light scattering. 2, fig.. VOL. 139. 2). due to suspended particles in natural. Dyer developed a device which essentially consisted of a light source that sent a beam of light through the sample. At right angles to the beam, a photocell was placed, and the amount of scattering was waters,. then a function of the output of this photocell.. The sample. cell. container, but this. used was. first. was. changed to. later. a. 2,\". x 2^" x 1" rectangular glass a 3" x 3" x 2" plastic cell to. handle a larger sample and at the same time defeat the problem of condensation on the outside of the. The. electrical circuit. was. cell. due to cold-water samples.. so designed that the output current of the. photronic tube affected the grid current of an amplifier tube, thus. causing changes in the plate current of the amplifier for small changes. output of the photocell. A microammeter with scale ranging from o to 100 was selected as an indicator of the degree of scattering and was connected in the plate circuit of the amplifier. The circuit was adjusted so that the output current could be zeroed for any given beam intensity with the sample cell empty. For operating convenience, a reflecting rod was so mounted that it could be swung into in the. a fixed position in the light. on the source. tained. of the photronic. cell.. in a glass-fronted. As. beam. light output. The. in order that a. by means of. entire unit,. check could be main-. on the output including batteries, was mounted its effect. metal case for convenience.. finally evolved, the device. proved capable of covering the entire. range of turbidity from Delaware River water to the. grade of. triple-distilled. finest obtainable. pharmaceutical water.. METHODS OF DATA ANALYSIS For the sake of uniformity. it. seemed desirable. to convert all the. hydrophotometer readings to "Equivalent Secchi Disc Readings," as. To do this required some relationship between actual Secchi Disc readings and hydrophotometer readings, which was not readily available. Williams, however, has developed an defined in a previous section.. expression involving the extinction coefficient as a function of the Secchi Disc reading, and since the hydrophotometer transparency. measurement. is. ideal conditions,. similar to the extinction coefficient it. was decided. measured under. to use this approach.. Let:. B. 3. Bo. = Illumination at the sea surface. = Brightness of the Secchi Disc as. seen by the eye..

SMITHSONIAN MISCELLANEOUS COLLECTIONS. I,. Hydroscope 3,. VOL. 139, NO. 10, PL.. in use. United States Navy hydrophotometer 2, Specially designed hydroscope. 4, Secchi Disc.. Mk. II.. 1.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. i,. Perauuameter.. VOL. 139, NO. 10, PL. 2. 2,. Scattering meter..

:. :. :. WATER TRANSPARENCY. NO. 10. Bb =. :. :. — WILLIAMS,. JOHNSON, DYER. Brightness of the surrounding water at the hydroscope depth. is the background against which the Secchi Disc is seen.). 7 (This. = Actual brightness of the disc at the disc. = Actual brightness of the surrounding water at the disc depth. = Reflectance of the sea surface. Rd = Reflectance of the Secchi Disc. Uv, = Relative amount of light going in an upward direction compared. B. D. BbD R,. downward direction at the hydroscope depth. attenuating medium interposed between the eye and. to. that going in a. D=. Length of. the. object.. d k. = Depth of the = Extinction. When. glass-bottom bucket or hydroscope.. coefficient.. the Secchi Disc. brightness of the disc. is. is. observed,. it. can be seen as long as the. greater than that of. surroundings.. its. other words, the contrast produced by the disc against allows the disc to be seen as long as this contrast old value for. Contrast. is. ^. human. above the thresh-. manner. —. Background brightness Background brightness. Object brightness. ,. In. background. visibility.. usually defined in the following .. is. its. [. where the absolute value signs are used to keep the quantity positive contrast is produced by a dark object on a light background.. when. In this particular case, there are two distinct contrasts to be dealt. with. —the apparent contrast, or that which the eye. contrast, or that. which actually exists. sees,. and the actual. at the disc level.. Using the symbols defined above, the apparent contrast Ca may be expressed as ,. Bo — Bb — —b Db. „ Ca. x. (0. and the actual contrast, Cn, by /. ^ Crz. \. (2) It. turns out that diminutions of contrast through an attenuating. medium. follow this relationship. CA=Cne-" D. (3). or, substituting the values for. we /. CA and CR from. (i) and (2) in (3). get. —. Bo o Bb Db. v. (4). Since the. BoD BbD BbD. B. is. BbD BbD. = BoD 5. e. _fcn. the brightness of the disc at the eye, this. amount of. sunlight reaching the eye. from the. means. disc. is. that only. involved..

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 8. Let us derive an expression for If there are. ables.. RB S. 8. B. amount of. {d+D). terms of some of the other vari-. in. units of illumination striking the sea surface,. s. units will be lost. B. owing. and B s (i—R s ) will be the water surface. At a depth of (i-R )e-k ^+ D. to reflection,. light actually entering the. now. the light value will. Since only. Rd. VOL. 139. B. be. s. ^>.. s. of the light reaching the disc. reflected. is. from. it,. the light just leaving the disc would then have a value equal to. B {i-R s. a. )e- k U+D ^R d. which. ,. B oD. (5). is. B oD. .. = B,(i-R. 3. )e-. Md+D). Rd. Traveling back upward, the light would be further attenuated over the distance D, so that at the bottom of the hydroscope the brightness value would now be equal to B (i—R )e~ k( d +D '>R e- kD One more -. s. d. s. reflective loss occurs at air-glass-water interface. sumed. .. which may be as-. to be equal percentagewise to the original surface reflective. loss so that the object brightness at the eye turns out to. = B (i — Rs)e— B R {i—R,Ye-. k(d + D). B„. (6). s. d. s. R dD)e-" D (i. kia. ^. be. — R.). Using the same methodology for calculation of the background brightness,. we. get the following:. B b = B,Uw(i — R ) e-" D B iD = B,U«(i — R.)e-* u + Di z. (7). s. (8). When lowing. is. (5), (6), (7),. and (8) are substituted back. in (4), the fol-. obtained. B R d (i s. — R.ye-kii+2m — B.U«(i — R.ye-" D B U w (i-Rs). 2. e'. s. w e- B,R. d. {i. —R. s. )e-™. +D). kD. — B,U w (i — R. a. )e-. kid+D >. B U w (i—R,)e- k(a+Dy s. which, upon simplification becomes z. — — —— =\nr^—) R d e~. >.. (9). Uv>. (. Uw\. d. u:. _tn. e. Clearing fractions and transposing: Uv> \ ( Rd Rd / \. --2fcD. Letting. -~=A,. by. e. 2kD. Co. when. Rd. — (i — A)e-*D — A = o. to give positive exponents,. Ae which,. Uv> __ _. and simplifying, gives: e*kD. or, multiplying. -kD. 2kD. + (i-A)e —i = o kD. solved for e kD gives:. *"=ji=vi. we. get.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. or in terms of natural logarithms:. JOHNSON, DYER.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 10. R d = o.S,. or, since. X=. A. VOL. 139. 2.3. — O.I + logyf-.. x vs. D may now be made, where x is calculated from which hydrophotometer readings which give k and Secchi Disc readings which give D were taken simultaneously. This plot plot of. stations at. shows a marked variation of U w as the Secchi Disc reading is is the graph which was used to determine unknown U w values when the S.D. readings were known, both for stations which had hydrophotometer and Secchi Disc readings and for those which had only S.D. data. By means of this methodology, then, it was possible to calculate equivalent Secchi Disc readings for each hydrophotometer reading changed, and. taken.. DISCUSSION OF DATA In the two appended tables, are tabulated. Table. I. all. the data taken on the Elsie Fenimore. includes the hydrophotometer and Secchi Disc. data presented by seasons and in geographical order from North to. South. Winter ruary, and. is. considered to include the months of January, Feb-. March. ;. ber.. The. ;. (figs.. July,. ;. and. various stations. series of charts. —April, May, and June summer— — October, November, and Decem-. spring. August, and September. fall. may. be easily located by number on the. 1-13, preceding the tables), which show the. and longitude of each of the stations mentioned.. latitude. Table 2 includes vices of. all. the other data taken, utilizing the various de-. Dyer plus a few others which were. also used.. These data. are presented in simple geographical order, proceeding from north to south.. The data. as a whole, although being. many. among. the most extensive. and shortcomings, and these should be kept in mind while any attempt at utilization is being made. The hydrophotometer readings were taken with utmost care. However, the calibration in air was apparently not standardized, the adjustment varying from 92 to 96% T in air instead of 92 percent as previously mentioned. This would have the effect of making all readings above 90 percent highly suspect since a small change in at this end of the scale is associated with a large change in the Secchi available at the present time, have. limitations. %T. Disc reading.. This. is. probably also the reason for the significant number of read-. ings which are above 100 percent, and hence change. readings to qualitative.. This 92 percent reading in. from quantitative air as. being the.

:. WATER TRANSPARENCY. NO. IO. equivalent of a. — WILLIAMS,. ioo%jT reading. to the data takers,. which. written for the U.S.. is. in. JOHNSON, DYER. II. water was apparently unknown. not surprising since the instruction book. Navy Hydrophotometer Mk.. II specifies a cali-. bration setting of ioo percent in air.. The. Secchi Disc readings in general are undoubtedly quite reliable.. However, any taken when the sun was low. in the. sky or in the shade. of the boat are probably doubtful.. In table 2 are given the remainder of the data taken with instruments other than the hydrophotometer or Secchi Disc. These data have been tabulated separately, since their meaning is not as well. understood as those in table. An. attempt was. made. to. I.. deduce some sort of a regular pattern of. transparency in the area covered, but no regular pattern appears to exist.. This. may. be due to the fact that. all. stations. were not taken. simultaneously (a physical impossibility), although this essarily so.. more shallow. cially in. is. not nec-. Previous experience indicates that local conditions, especoastal regions, almost completely determine. transparency conditions at any one point in space and time. Thus the turbidity will vary. one time. from one place. to another,. one depth to another,. to another with seemingly constant environmental conditions.. These data seem to emphasize. this. seemingly unpredictable nature of. transparency in natural waters. In general, however, the data do show the following expected. changes in transparency 1.. An. 2.. A. 3.. An. increase in transparency with distance. from the. coast.. seasonal change in transparency, with the winter months. seeming to provide the greatest turbidity. increased turbidity around heavily industrialized areas.. These three [35]. m. are, of course, to be expected, as outlined. by Williams. a set °f general rules for predicting transparency based on. geographical sources, etc.. location, weather conditions, proximity of polluting But there are so many variables to be considered simul-. taneously that these generalizations are often invalid.. This information. is. therefore presented not as a basic scientific. study to determine the causes of transparency variations, but rather to present actual conditions existing at particular points in time. space.. and.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 12. VOL. I39. BIBLIOGRAPHY Anonymous.. 5.. Electric camera for deep sea photography. Sci. Amer., vol. No. 20, p. 483, 1917. Submarine camera. The Engineer, vol. 129, p. 658, 1920. Armstrong, A. R., and Ewing, C. W. Studies of the measurement of submarine illumination in Virginia waters in Chesapeake Bay. Virginia Fish. Lab. Contrib. No. 13, 1944. Atkins et al. Measurement of submarine daylight. Journ. Cons. Int. Expl. Mer, vol. 13, No. 1, pp. 37-57, 1938. Bigelow, H. B. Oceanography of the Gulf of Maine. Bull. U. S. Bur.. 6.. Birge, E. A.. 1.. 116,. 2. 3.. 4.. .. Fish., vol. 40, pp. 511-1027, 1924.. Acad. 7.. A. second report on limnological apparatus. Trans. Wisconsin. Sci., vol. 20, pp.. Birge, E. A., and Juday,. 512-551, 1922.. Chauncey. Penetration. lakes as measured by the thermopile.. of solar radiation into. Bull. Nat. Res.. Counc, Washington,. vol. 68, pp. 61-76, 1928. 8.. Boas, F.. Beitrage zur Erkenntnis der Farbe des Wassers. Inaug. Diss.,. Kiel, 1881. 9.. Boutan,. Memoire. L.. sur la photographie sous-marine. Arch. Zool. Exped.. Gen., vol. 21, pp. 281-324, 1893. 10.. Bumpus, D.. 11.. Clarke, G. L. Light penetration Mexico. Journ. Mar. Res., vol.. 12.. 13.. F., and Clarke, A. H. Transparency of the coastal and oceanographic waters of the western Atlantic. Woods Hole Oceanographic Inst. Techn. Rep., vol. 10, p. 10, 1947.. No.. l 93%-. waters.. Woods Hole Oceanographic. Inst.. Collected. Reprints,. Contribution 26, 1933. Observations on transparency in the southwestern section of the .. •. Variations. in. Clarke, G.. L.,. Res., vol. 4, pp. 221-230, 1941.. the transparency. throughout the year. Ecology, 16.. 85-94,. .. North Atlantic Ocean. Journ. Mar. 15-. 2, pp.. Light penetration in the western North Atlantic. Woods Hole Oceanographic Inst. Collected Reprints, Contribution 101, 1936. Observations on the penetration of daylight into mid-Atlantic and .. coastal. 14.. the Caribbean Sea and the Gulf of. in 1,. of. three areas of the. Atlantic. vol. 20, pp. 529-543, 1939.. and James, H. R.. Laboratory analysis of the selective. absorption of light by sea water. Journ. Opt. Soc. Amer., vol. 29, pp. 4355, 1939. 17.. 18.. 19.. 20.. Darby, H. R. Johnson, E. R. F. and Barnes, G. W. Studies on the absorption and scattering of solar radiation by the sea. Carnegie Inst. Washington Publ. 475, 1937. deSybos, Donald P. Transparency by black and white Secchi Disc of the water of Long Island Sound, Block Island Sound, and Newport Bight, cruise Stimi III. Cornell Univ. Status Rep. No. 18, 1952. Helland-Hanson, B. Physical oceanography and meterology. Michael Sars North Atlantic Deep Sea Exp., 1910. 193 1. ;. ;. Hunter, G. R. Underwater camera world. Pop. Photogr.,. vol.. 17, p. 42,. 194521.. Hutchins,. L.. W. Buoy. (Unpublished.). data at. Woods Hole Oceanographic. Institution..

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 13. A., and Bowen, I. S. Transparency of ocean water. Journ. Opt. Soc. Araer., vol. 36, pp. 617-623, 1946. 23. Jerlov, N. G. Optical studies of ocean waters from reports of the Swedish Deep Sea Expedition. Vol. 3 (Physics and Chemistry), No. i, pp. 3-59, 22.. Jenkins, F.. 24.. Johnson, E. R. F. Undersea cinematography. Journ. Soc. Motion Picture. 25.. Joseph, J. Durchsichtigkeit Registrierungen als Oceanographische- sich Untersuchungsmethode. Deutsche Hydr. Zeitschr., vol. 13, Heft 1, p. 69,. 195 1.. Eng., vol. 32, pp. 3-17, 1939.. 1959-. 27.. Undersuchungen uber Ober- und Unterlichtmessungen und iiber Deutsche Hydr. Zeitschr., vol. 3, Heft 5/6, 1950. List, Robert J. (preparator). Smithsonian Meteorological Tables, 6th rev.. 28.. Markham,. 26.. .. ihren. Zusammenhang mit Durchsichtigkeitsmessungen.. Smithsonian Miscellaneous Coll., vol. 114, pp. 214-218, 195 1. J. J., and Perry, G. R. Oceanographic stations of the New London Laboratory from May 1943 to November 1944. Columbia Unied.,. versity, 1944. 29.. 30.. Pettersson, H. A transparency meter for sea water. Medd. Goteborgs Hogakolas Oceanogr. Inst., Series B, Band 3, No. 8, pp. 1-17, 1934. Poole, H. H., and Atkins, W. R. G. Photo-electric measurement of submarine illumination. Mar. Biol. Assoc. U. K. Journ., vol. 16, pp. 279324, 1929.. 33.. Powers, C. F. Deubler, E. E. and Backus, R. H. Transparency by black and white Secchi Disc of the water of New York and Newport Bights. Cornell Univ. Status Rep. No. 15, 1932. Secchi. Esperimento per determinare la trasparenya del mare. Cialqi Sul Moto Onaoso del Mare, 1866. Whitney, L. V. Microstratification of inland lakes. Trans. Wisconsin. 34.. Williams,. 31.. 32.. ;. Acad.. Bay 35.. Sci., vol. 31, p.. Inst. .. ;. J.. A. 155, 1938.. small portable hydrophotometer. Techn. Rep. Chesapeake. In press.. How. to find clear water.. Water World, May-June,. 1956..

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 14. 54°. 111 >l II. II. llll. VOL. 139. 51°. 52". II II II. I. III. I. I. I. Mil. I. II. III. I. I. I. LLIil.l. II. 'I. III II. I. M. 11/. I. 51°. 52*. 50'. AT. 4S'. -. 1. I7i. 1. 1. 1. ii. 1. 1. 1. 1. i'ii. 56°. m. 1. 11. 1. n. 1. 11. 55°. 1. 1. 1. 1. 11. 1. 1. 1. 1. 11. 1. 1. 11 11. 1. 1. 1. 1. 11. 53°. 54°. Fig.. 1.. 1. 1. 1. 1. 1. n m 1. 1. 1. 52°. 1. 1. 1. rirn rn n r. 51°. ii. |. ii\l. 47 9.

1. WATER TRANSPARENCY. NO. 10. 62°. W. 1. 1. 1. — WILLIAMS,. JOHNSON, DYER. 15. 61. m>. Of St. 1 m. ^""WSSflJ?* 8. +**?. 47°. i v. \. 1. 1. n. ii ii .. n. 1. Cl°. 1. 1. 11. 1.1. 1. 11. 1. II. or. I.I. I. I. T. 1. 1. j. i. 1. 1. 1. 1. f. 1. 1. 1. 60°. f. .1,11. 1. 59°. Fig.. 2.. 1 :. 1. 11. 1. 1. 1. nil a. S8. 1. ,. 1. n. 1. 1. ,. n. 1. i. n. 57^. 1. 1. 1. 1. 1. k.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. i6. 63°. ki. 1. 111. 1. 1. 1. in. 1. 62° 1. 11. 111. n. 61°. 11 11 11. 1. iii'i. n hi. 60°. .. 1. 1. 1. 1. 111. 11. 1. 1. 11. VOL. 139. 59° 1. n. 1. 11. 1. 1. 1. m. 5S° i. l. 1. 11. 1. 1. 1. 1. 11. 1. 1. 1. 1. rrn\. 46". 45°. 44" Sable Island. 43°. 43°. 42. Ay. !. 41'. i4i°. Fi EECD. 1. 1. 111. mi. 63°. nil ni in 62°. ii-ii. rn. inn. 11. n. in. 61°. inn 60°. Fig. 3.. 1. n in. 1. rrivin 59°. 1. 1. 1. 1. 11. 1. 11. 5S°. 1. 1. 11. n. i<3.

J. 1. WATER TRANSPARENCY. NO. 10. — WILLIAMS,. JOHNSON, DYER. I. 46. 44'. 43". 42°. * •. 10. ° l7i. *v & **. +. mi. 1. ti. i. rr. 69°. -ii r. 1. 1 t. 1. 1. 1. 1. 1. 1. 68°. 1. 1. 1. n. 1. 1. 1. 1. 1. 1. 1. 1. 1. 1. n. 1. Fig.. 1. 1. rri rri 66°. 67° 4.. nn. 1. 65°. 1. 1. r. 1. 1. f. 1. 1. i. n. 1. 64°. 1. 1. 1. 1. 1. N. 40. o.

i8. SMITHSONIAN MISCELLANEOUS COLLECTIONS. Fig.. 5.. VOL. I39.

NO. IO. WATER TRANSPARENCY. — WILLIAMS,. Fig.. 6.. JOHNSON, DYER. IQ.

20. SMITHSONIAN MISCELLANEOUS COLLECTIONS. VOL. 139.

WATER TRANSPARENCY. NO. 10. mi nun. 77'. 78". 79°. N. i. i. mi. i. — WILLIAMS,. iiiiii. i. ii. i. i. n in. 76" i. i. utiiitii. i. JOHNSON, DYER. m n n in. 75° 1. 1. 21. 74° 1. 1. i. i. i. in. i. i. i. i. i. i. i. 1. 1. 1. i. i. B 2o°. IT. 27°. 26=. 2<7. 25°. -2|k+. C R E A T. BAHAMA BANK. Hi. i. ii. i. i. nn mil i. i. i. ii. i. Fig. 8..

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 22. •85° 1. 11 11. 1. 1. m. 84" i. i. n. 1. 1. 1. 83° 1. 1. 1. m. urn urn. 85". 81". um. ili. VOL. I39. 7r. S(V. 11M111111 irnTT. FLO. R. I. D. A. 26'. 25'. -. 26°. -. 25°. 24'. 24°. 22". 21°. 20". 20°. 19°. 19°. l^i. 1. 85". 11. in I'M 84*. 1. 1. in. 11. 11111 83°;. 1. 1111. 1. 111 11 111111 11. 82*. Fig. 9.. in 8I°<. nun. 1. 11 11. 80°. in. 111 111 11. 11. 79°. N.

NO. IO. WATER TRANSPARENCY. — WILLIAMS,. Fig. 10.. JOHNSON, DYER. 23.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 24. 91°. yi. i. 11. 1. 1. 1. 11. 89". 90° 1. 1. 1. 1. 11 11. 1. 1. 11. 1. 1. 1. 1. 11. 1. SS'. n in) n. 1. it. i. iti. a «t:iei!. 23°.. •i. '. 1. 1. VOL. 139. 86*. 8J« 1. 1. 1. 1. 1. 1. JSAN K. 1. 1. 1. 1. 11. 1. 1. n. n. 1. 1. 1. 1. 1. 1. 1. 11. 22. 1. \+ \. 4*hf H. Alacran Reef. 1. ir. -. .. Fig. 11.. 22°.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. Fig. 12.. JOHNSON, DYER. 25.

26. SMITHSONIAN MISCELLANEOUS COLLECTIONS. VOL. 139.

NO. 10. WATER TRANSPARENCY. IS. i. i. 6%. I. i. 10 co *0 10. ~ ". v. — WILLIAMS,. d O d. K MP? o*M « J^ MO. 00 00 00. •S"«. 16 4 •«fc. •a. pq. <. bo. 3. \6 uS l<. 1-1. 1-1. >-;. VO t-^MD VO w> Tf 19. O d O O. ©* C> C\00. u-i. N. K 0055N00 *$"%%. Vj VVjvb "Koo 2 J "J. 27. I. iOh tlO^t t%\£> nWtOfON N ^A f Jf. CO. I. I. \00 rOTfOJO. O O 00 N.O O 't'+M n V O ^^^"fO^"^^^^. «o. i. JOHNSON, DYER. O 04. 5-.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 28. VOL. 139. 3P>. sq. ho 00. in.. ton. ft. H. t^. tJ-. tJ-. Tt ro rood CO CO 00. ON d\ CO CO 00. CON«t1N K.tN.l^.6. O. m 1-1. M. \T)\0 O O in m * O O OOOOO O00>0 « in W in K O HH*OWC*V)U)lfH01')t|HHMN(1f|MHMHHnni«)t. CO in. P™. OOOOuiir)iriinHHOO'tmo!) ul H. *d vd. CO CO. Oo. 0). 0). «. 00. 01. "+ O. ^O. N. CQ. Ou3 "00. <N. ^t. O. V3. N. 00. V o vb. oCo"^. 00.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 29. HMMHHHH\OOi£HOCiOi')>')0 '>i')\/HHNNftNNNNNt'lH 1. 00. N Tf K t in 00 iriinNKNNNKNKNO. oco O inirnnO loinioioiofiTtjvi. O t-^O. PS. co. 1 I. 1 en. 01. rf. PI.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 30. VOL. 139. Id. 00 00. rS^. £. H M. o? cq. '. M. C\ On. O. CO 00. o o 10. N. O. CO ro CO. O). Si. N. '. s. H H. o. ". N. o o. 00 vq di d\. m O O00. * 'to vb. ^. "?^. d 006. NiCOO. g.«. c? <o. no ad. d. "lO a. W. Vb vb. PI. o rxboo &, m. ©n On On Tt. 00. ddddokn. I-. O O. On. t/->. roVO. 01. Voodoo M q- %t *b ^b M3 \N. (O. -t \r>\Q.

NO. 10. oo« h h di. d. o". WATER TRANSPARENCY. vqoqvo 10 d\ omoo t^MD d\ 0\. — WILLIAMS,. q\oq>oq\q\r>vovq. vq. o o o. JOHNSON, DYER. o o. d\ 0\ o*. &. <j\oo \d. 4. vq. o. c*. do d. o. 31. on q\ q\ o> ds d\. f^i-ii-iOOOr-sPOOPlOOQr^OO O\00 NOaHOnOKOOOOittO; NfOcoror^CONNNi-ciH NMnMNNNNPlNH COPlfOPJCiPlNN. o. fn. w. 00. Vo^. pi. 00 >*. o. \o. o. ^b. "pi. °°. *. o. vo. "pi. 00 "V "o vo. own 00 Vb i>. £. o. Q. pi.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 32. VOL.. 1. 39. BO. 0\ C\<6 TT. o o o. H H OiO 6 d\ & o. o\ t>.vd. O'OOOO. Oi-iO'-''-'OsOvOOinrOOO>-. ,. >». a. an,. 3 to. d 6. MNOOni-. ,. a. '-'»-..

WATER TRANSPARENCY. NO. IO. nnn 60606. OiKO. owo. to. to. Tf"VO. — WILLIAMS,. vq co. o\ o\ On. r>.. M M « 6666660 .. 6 o. JOHNSON, DYER. to fO. to. t^-ioO o\od t^. m o o o O. iOiT)OONNNPjNOQ\t^fO>nNO>-<MNNMNO 50ioOOO cocotOtOCOtototOtoC) N w to to to m totOcocotOfOtocoCl ,r. C». C\|. \o vo. w. ^o. h. So. ,_,. ,_,. C). hi. o iovovo t co^r Vo. i-o'S, ^ "g. cn. to. ^. w. 33. O. 00. *. ON. o. Q. vb. CI. ,. -. |. to. 00. On G\. 0\. «. ^1-.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 34. VOL. 139. •a.. 3Q. h ao vo t^»o o 10 hoo'O oqoq o»\o h ddio6dd>N.ddid\di6oodddiONcoodd. ;q co *r{. •g '-5. oooiOtOHOoineocooNHOOHaoiOiniflNON. o i> «o m. n 00 "Vo <! mvo ^r. vb vo. Voii n 00 "V*b oJd«5o ^-'i-ii-inc'jco^-'* iovo. 00 to vo "n «. 1. I.. —. w •gfc. S. .2. vo. 1. to. o. CL,. U ifci. o. cq up. vo. h. 0000. V "oco vbo "w ww. vb vo. vo. c. «*i. n»o. GO. Q. C u to. •*$•.

WATER TRANSPARENCY. NO. IO. oo 10. mo. louivd^o. I—. 1— l. I. t— <. t—i. 1OK00 Q. t. —. 1. 4 1—1. vqMD^qiowvqto. o\*o. oo. 4. iom in.o dvOidsodod M 1— 1. ON XO 00. — WILLIAMS,. 1—1. N "^O. NNNOM. JOHNSON, DYER. nnnw ^. n. in. p o\oo d\oo MWMIHMI-lh-lNMMeil-l. ts'^i^t^.tN.»>.i>.od. lOfOPJ. "<fr. •*. T. S? S5. O. 00 IO ,g\ up. io. 35. is.. vp. tovo^f. ^. oo^^^n°^^^ Mo ^^^^n^s°^2. 8. a. a. te. O (3. U. 5 o. 1. Uh.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 36. •SO. h. 10 10 up 10 "9 "?. m m n n >-''-<i-ioo i-i. foo. h. co. m. \q. *0 OO VD 00 O ^^ ll (l 1( ll ll |. «. cc. _. _. _. -i. 1. _. _. i-HMnf-ii-ci-ii-i^i-ii-iCMCo. -<. m. t«p. lOOO ^t. m. « urovo. 1. ,. -tNNOOOOOn t fj p; « * t m. ^-^. CO. to fj. VOL.. w. i-i. CM. co fO "T. 'IS I.. w "O. _. •2z. >.. pq. m. u. its. its. c. c. 39. 1.

WATER TRANSPARENCY. NO. 10. cqcorj-Tt-Tj-iNto. oo^ooq In.. l<. In.. CO. tN. «>. l-s. tN. IN.. ^O. &. -a. e 3 O u. a o. *o. a. °>. CO. ^. iOMD. In.00. JOHNSON, DYER. m inioooooocooo. oooott. 2>7. \o "? "?. 'Oin^M^NNNNtsCOOOOOtsKKN'i-t'iM V. \0 in\Q {n,VO VO Tj-Tf-^-oO vOtJ-o*. O Oil. — WILLIAMS,. CSO w. <N. w m u-)>00>0^0. 1t Oo. ^. n K KVO^O. CO ^f in VO. In.. 00. ^. -*(N CO. w o. O w. co. (N. T.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 38. VOL. 139. 2Q 3«5. .Sq. HHHHHOOOOMCfNHlOWHIONlOnMMC'*. l-l. WM. •£•.3. >/3. VO. V NOO 00 00 00 00 \0 *0 >0 iOrl-00 N O On 00 O m O Ov GO vO ifl * N MWWWNl-ll-ll-ll-IMt-l M |-|MIHIHI-1IHMI-It-IMM. 00. S. o. 2. T. *. 5> H. <. pq. ua. "^ Vs 'V "lo md. "K.. So *b\ "b "m. "oj. "to. *•<*. o. Si "n. V> "rr loo "K 00. "b\. 0\. "o "w.

WATER TRANSPARENCY. NO. IO. IOIOMVO 101-1. lOlOVOCOlT). mmmjco iom. 'fOOC0OM')O M H*. S3. E? S". o. 3. h-l. i>. S. co '3-. 00. Pj. t>.iN.oo t^ in *o 'O. l') |. — WILLIAMS,. H m. JOHNSON, DYER. OOPlMHMC(f|tmOOiOO—. ^. "*. if?. «-^. ^. \Om. 10 IO lO^O VO \0 't M ts.t-it>.tN»\d 10 ^r. ^f4inioH\dio\d. tHMC^HHI-Ht-H. o^b w. 39. »n 00 "o\ "b. s. "JS. V. 5. t. (. "^. ,') |'). —. I. t. o. —. I. I. tj-. fN00tnN. ,. ^-1. S3 "«. i—|. "K 00. "os. "b "w.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 40. VOL. 139. 3 jaw. »Q. -Ohj. tf 1. p6>-<. t%. in.. hh. m. « "^ o. ^c. 00 -<tc6^o io»otoT}-Tfcvi. d o. d. d\ di. h. id. m 00. m «. K)i()U)ir)iniOTM«!<<)(1«t(flOiaOOiOi^. i-i. «. i-<. 00. V. o. in. n. 00. Vo i). «. 00. V o 5i. n o. ~-. vn. ' -. M N. 5o «>P? °° r'T.

NO. 10. WATER TRANSPARENCY. O. I. v">oo. V. qioo. o. o. ^j-co vo. I. «o. I. A. + ooo"*-e»|Y. — WILLIAMS,. "M. i. 00 CO CO. p. 1. I. I. 1. ^o. vN. OoOO ... pq. '. 1-1. VO VQ. M O. to to -3~--~. o. ^r "\ IO. umiO M H. 01. ,_,. 00. 1-1. co to co co co co oootoooo^-tto-'tOti-otooo IO lO "HO "^ ~\ IO ION >0\ IO ") "). IT). "--.. ifl. ^s.. If). iniOvOMvOvOvOvONWMNOONOONOOOO. NNNhNNNNhhMmpihMmNNN. 10 o) JO JO jo JN JO "Vi *n "K.V. O "on "»o V) V> 10 Tf t TJtO^-LOCM fOM lO'*TfTj-'0<O "~ __. i. 1-1. cococococococococococococo. <o to <o <o. U. U U. bo. G. o. > ^J. G o 5 .2. >> .-s p-i. 2 bo 3 G O O. o. P-l. tf. § p 5 K h u g S. <U. O. Q>. to. fcG. £-. o O ^*G >. o. Et3^. ,C. <£. t-H. 4-. £ co co S 8.e « £ a G -2 — C C G C r/3 r* 5 6 O 2 5 2in 2 ^ ,G cS G — c ciUj CJ <U 4> 4> O " *U " j_, G LO^O CO *u! a rt cc rt w 2 •. •. co. 1-,. 1. i/i. Ou <PhO. 6U «TU "S« «. Q. ts). <j\. +. 1010 O 101O10O O O ^s* c o romiOMiO'^O *o o v- ^- Nifl ~ "1- (N CO CO to tj- co -" O i«)Mno <ovo ioowoco a n Oh w c\ r-x - O M Oi-ii-iwOOOihOO"-iOmwihi-i •"'. l-l. cn. I. It CN. 41. o. i^-|o|"?|>-<iomi^nwo A A. ,. co. 1. JOHNSON, DYER. t/). J S* SOU UUUU W wOWO ,C -G JC. eS. .JtS. ... ... _. TTVO00. ... ... TfO. VO t-t.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 42. E. •. ^C/J. ->3-od o "Sc4 ci H W M |_|. >_|. o\. >-<'. I—. HH. ^j- 1^ c\ oi 000 "^Kvo^ovdvo tx^f MMI-"t-ll-H|_| »7 **i-. VOL. I39. \n d\oo 00. H H H. A 9. t^M3. *. o coNN, -. Lj. *». O m w. "INOiO. "^. „•.«.•.•.» CO Tf-Ovo <M <N. rv-,. rn. "t. MNCO N O CO +. _. _. ore MOO. ~. t ^O O ... 00 <?>. O. £n. -»«... NC0 "^. ^i--. ° ^ °. -_ ^2>.

NO. IO. to. N. IO. WATER TRANSPARENCY. ts.. VO IflH (TJOOO. ts.00. N. 't. (IW. 4. fO. O00. — WILLIAMS,. PJNONNIO fTJOO. M w. w'. m N00 O. JOHNSON, DYER. C? 1000 00. <0. ir> rj- rj-. 00 ih. ->i-. l-HMIHIH01l-l>-"IHI-IMN'<^C^I-llHl-(WI-IT}-Tr>-ll-ll-l(-ltH\O'-. \o. N. t<, v£>. \©. N. ^0^2. I. ^O. %. iCO T m O VO N ro £J. ^--'l^OVO t^l ^ ^. ^T CO f. 10. M \/. 1. MVO W O^O M CO t O ^O 00 O t^ GO *^f CO^"^-'*m\OVO t^O\l tx CO C\C\°. 43. "">. ^. 1?. o. &. o. bo. to its. to. u. eq. O. u. -5.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 44. 1-4. <J. VOMD. A °9 ffi. VOL. I39. «. T. 5. ^. "^. ^^+ o. A O. 6. rrjOO. §8. km. -1. C\. mm. 4-. t^ fO. * ^2.0. ^. <*3>0 1. CO. 1-1. C3. N. ^. N. ^. o. <£. CO. tn •* *t. 1 A. TO. ^OC o. 00. H W P)«. t^ CO. C*i.

WATER TRANSPARENCY. NO. 10. — WILLIAMS,. JOHNSON, DYER. 00 vo. In.. 10. 10 in 10 10 ir> 1000 r-s 'O 0\ ro ^f Ti" ^f to VO O i«i h. 00 O in 10. O \0 O rf Tf- moO O ^t "1 K N N "3" 0) ioif)iom\oionifl ")iO (fl. 00V0. o. \o "w °°. >-h. 45. o\oo r^^. KN « NKiOK I. ^^ O. -t. ^O ^O >0 'O. ?o vb osoNM-tbo. o. I. I. m fTO OO tx t^ l^. I. I. I. I. I. I. t-^. t>. In.. Si "n 00. %t "o no. 0000000 f O Tf. to 10 i- to in. OO 00 On. O. O o o n ro O CO 00 ih O « 1-1. O O. 1-1. N. ro CO to to CO. nN. o o. to CO. 10 HI. t-4. if). M. m 1-1. 10") hH. IH. 0000000 OOOOOOO. tO,JO CO to to to tO 10 ir) in "io "io "io "10. cq. ...... :. in. '.'.'.::. :. *. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. :. jd. u. O. P <u. O. Q. Q. 6 6 d 6 id "HQQQQQQ. o.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 46. SO. •SQ I. I. II. I. I. I. I. I. I. I. I. I. I. f\J. -!. I. I. ^N_^_^ N. I. I. I. I. VOL. 139. 1-1. I. I. I. W. 000000000000000000000000000 Mio. 01 m^D CO 00 <N louim O O uiirj t (0>OfO^'t'<tinTt-'tTrQ h O w N Tf mvO CO o. In.. t. in. h. m CO. C\ >n w in io^oco in co co 1- O 10 rf t-i T|-. o O. no TTVO tJ-cO COCO O M 00 CO ON 0\ .hwOi-ii-imi-hmwwp-hmOi-iwwwOOOi-iwO'-ii-iOO. 10 COCO. ii rt. £ '. u 3/->. .tJ^. W> w o. t-i. i-c. CN. <N. Tr^^Tr^^^^^TrTr'^Tl-Tj-T^-Tj-T^-cnfOCOCOCOCOCOCOCOTr ^^\^^-^^-^^-^^^^\ CO OOOOOOOOO O CO CO 00— CO^^~^TfTfr]-rJ-r)-T}-TtTj-Tt'^ ^ -^ ^ ^ ^ \ \ \ VO co. -~,. <N i-iiHi-iHi-ii-ii-ii-iMMroroC )aoc>)OICOVOiOiOiOTrr]-r)-rOi-i ,. uimicminioifiioioioinioioi'iinuiioi'iinui "in "in "in "in "in "In -1 M J - J" H J J -!" J J J J J J J" „M J J ^ J" J J. M J J" KKNtsNNtNtsKNNKMslNKNKNNKNNtsKNN OOOOOOOOOOOOOOOOOOOOOOOOOOO 00000000000000000000 °oo°o°o 000 C0COCOCOCO000000(X)00COCOCOCOCOCOCOCO0OCOCO00COCO00COCO J. -1. -1. -1. -1. -1. -1. -1. 1. '. «.. .I. -1. 1. -1. >?. -1. -1. 1. -1. -1. 1. -1. -1. .I. ... "b "b "b "b "b "b "b "b "b "b "b "b "b "b "b "b *b "b *b "b "b "o "o "b "b "b. j>. ^^-,. ^ «£, it.". jo cojojo cojojojo cojo ro cojo co co en cojo co <o <o co co co co in in in "in in in "in in in in "in in "in "in "in "in "in "in in *in "in "in "in "in "in "in "in. ,5*5. m OOOOOOOOOOOOOOOOOOOOOOOOOOO. OvOvO\0^0\0\OMD\OvOM3vOC^OvOVO\Ov0^nOO\OvOvovOO\0. j. •. §. ;. •. j. •. •. ••*•••••. 3 w .2-. •. j. ••••••••••; .. .. O w. -. *O Q. jh "3. rt. CQ. ^. £. £. J.«. ::::::::::::::::::::::::: £ ... :::::::::::::::::::::::: :h3 .. .. ^ 0". 6 b. 0". 0'. d d d d d d d d d d d d d d d d d d d. "c3. •HQQQQOQPPQPOQQQQOQQQQQflQQQ'H a. 3. rt. ri. h-1. _1. I-. L,. O. O.

WATER TRANSPARENCY. NO. 10. — WILLIAMS,. JOHNSON, DYER. 47. £. I. N irj. in in. N. 00 00. 00 t^OO. i-<. i- 1. I. 92. t^. 9*00 00 00 qo t^vo to ro nnnO> oooooOvA ONO\ChO\0\0\CNCh. iooo c?ioo. oooooooooo O m M. fl. * m\Q. t^OO. M. tN.t-^r->.t^r^r^(^tv.£.r> o ooooooooooo ooooooooooo ooooooooooo OOOOOOOOOOOQOOOOOOCQCO ,. u">m»om>0»niom»n>n»n. OOOOOOOOOOOm ooooooooooo vOvOO\OOM3\0\p\00^0 "in "in "in "to "in "in ui. 10 10 in. NNNNNNNNWN01. !. I. I. !. !. '.. '.. '.. '.. .. I-. ::::::::: :^u ::::::::: :K OOOOOOOOOOW o3. to. QQPQPQQQQQ^. 60. fa. 01. O. ro.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 48. CO ON. •3R 1-1. " «—,-. _. OOO OOO °S. 0000000. O. smpq _. I. I. O 6 I. O O. O. n * nm o n SoooooooNoo^oooooomo ^ hO OnvovO O O mi-imihOi-i>hOO> u .. f^. fl (<) On <0. 1-1. (O. £_,. «. to. WX W. -. (O to to 00 On (n). CO. *>-<OOC\1i-i. 000000. M'ftOtOtOtOtOfOifl'O'OiOlO'OO rt. q. 1. — & C\ N (O ©NOO "^ HH0\O00 0000HHHNN„Ht0 tOtONNMNNNNNNNtonto hi. N. I 10. \r> \r>. in. m. in. *£ Cw I. «. W £ •B^. <. CQ. a. ns. O. d d d d d OQQQQQW. *t:. X. <v r8. g. o. u O.S-". a!. (OmN. IH-C<Nl—<l—1>—1>—11—II—!•—. I—. AAAAAA ++++++ o o o o o o N. w£. 00 1x00. VOL. 139. 1. *~>. A. +A°r° t K'+oo 10-0 tg,!, tiDMnTtT. o\cc>^ii-)iooo. ". vo. O £J. 00. *. O o. ^b. £j. 00. °o 10 Tf. 10. O. o o CM 1-1.

NO. IO. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. I. \o. n. o. o". Tt oi. ci. m. inmiow VOh. m *o "^SS OvOO O. AAAA ioroio« + A + A + A + A t co CO rf Tf rr § g § §. in moocc CO CO. 0\0\Oi. "S-^O "- 1. O vo '-'. f. *i. O. r. co. I. Nir>t»jfO *> "? *? <*? *^ c*i co oi co <o. 4. mm a? 00o. I. °° <*? *> 10 rt-vo *d. o. *? co co <0. AAA i-o. 0\ ON. 4 A A. OOmOcOO*0<OmOOOO -t. m. 49. OWMI-ll-ll-ll-Hl-ll-l. a. _i_ _|_. too. XXX >oo 1-1. M. 4. h-1. " o. to. mo.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 50. VOL. 139. *3~ ?.0. s. 3. •. aN^oo m A. °o. m. upio'jtiriw. d 6 h. l-c. \/-). °i 5 «. t:. 00 I. 04. •.. -. *. «.. CO rtOO. vo. W. WhV V _. «.. «.. w w N. ". ™. =o <a. •rj-. \o 10. 1-1. M M. Tj-VO. vv. ^. In.N In.. 0*. _. .. CN. N t^OO NO VO lO. ONOON AA M. CQ "jopq pq. N. ^. -pqcqpqpqpQ.

NO. 10. WATER TRANSPARENCY. WILLIAMS, JOHNSON, DYER. in uj wp cj 0) t>. u^o 10 10 'Ovovooio^ovo'oioi-ttovoioio'^rioio. V. OOKKK'tKOOKioO. ^b "^ 'S. w. o. o. Q. i. «. «. ffl. ui ts^O. m. mm. m. 10 10 t\ 10 m'O to in 10 m'^o loirnouiTfioir/i/iioiri. mtCmioioioON. o^b'^^pq. 5. oi^fl. iflC. ^. w. uiuin'tioi'l^fio. co pq. o^ncow. o.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 52. VOL. I39. 3Q. ww. vvvvvvvvvvvvvvv. a^. -<tiOiOiOOOOOOOOOOOOOOOO. •5 ft. r>,. -. OICOCQ. 03 1. o H O CO w. in. CO Cn. 1. ^. O^b N. ~. 00. TOO. ~. ~. ^. ^. ^. oth MOO. + -O «vO. ~. _~~^ 00 TO. oil N. o. to.

NO. 10. WATER TRANSPARENCY. \QMMIHIHtHI-ll-4>HM\0. — WILLIAMS,. JOHNSON, DYER. lOli_)lOW)»Omi/") U")»0"'>lJ">lr5MMl-H|-!l-l|--l>0. WW. VV. V. 53. >. «NNNNNN0INtintOHMHOOHHOOOOM0|IN«tlWfln. "n 00. "V "o. ^b. o. \b. "^ °°. "^ "o. sb. o. \b. ""^. 00 *•* "b vb. c. 3. vh "n °°. "f "b ^b. O. Q.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 54. .^q. iflioioio h. w". vvv. i-c. louiirjioioioiouiuii^iflioH. vvvvvvvvvvv. in. m «o. 10 in 10 10. vvvvv. lOOOO04CS(N*HOOOOOOOOOOOC^iOiOOOOOO. VjB. S. i-c. VOL. I39. (. 00o«00^00ob. §. >. IE. (,|co. ,t .. £ ,0 0^ <«)^0\0o^«oo''' f f. ;.

NO. 10. WATER TRANSPARENCY. in in in in in in. « M h. M. >-i. o. ooono. <-i. VVV V vv. S«. °. — WILLIAMS,. k*. ^. tj-tj-iom _, tx « "? ""J co cd cd inTtts.ts.ds'-<odcood <x>. N hco. M pq pq °^ i £ i. 2. ifllN. 12 3". «) rf 10. °. ^. 2. O. 00 CO. o>. JOHNSON, DYER. t\^o <J 10 >-'. in.. toN^ooo >-. t>.od. r>». >-i. vo\d 06. 55. t^vo. do. h to>-<iou-)OC^MOMi-iM>00. £o?°o. 2^2. ^00. ". 00. J*. o. vb. £j. <£ Jt.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 56. 5R. •sq. VOL. 139. :*. o»vo»ooo io 1-nC>CJO in 06. esq. li. poq'o. 00. tN.\0. l. On. voro\oo»oN'o<~oOo<. <3\. ^. O. h. 1. u?. tv.iO. vowc^. n^o o. dd. o. o. d\d\>-i. to <n. ^d. moo 00°. oc. 5< oi-ioiioo'^"r-^oO'^'C?\r^iooON. v,. ,. ^3. O. 1. 00 v H2^jf °^ v^'^ °^y^ ? °^ M. ^o. ~<N. 2?^ °«^. ?. c. *.

NO. IO. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 57. ifliOtOO'tNNONOMinoMvO^( 100iflPI«\01''ttninN«N (OmPlMMNtiOMMNTttOMH m « m N ,. 01. ^00. Tf pQ. o. ^b. N. °°. ?0« NOOVo. <N. WOOVovb. otn WOO Vp3 Oui. O. Q. Q. N*V o.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 58. '3. Q. .. w woo. vv. "i. O O r^O. *°. a. cs. 2 « 1?. ^^. CO. f*3. •"<". m. VV. lom3 t<.M. o o w. V". VOL. 139. c^cocooooooooooo c^d\od. d\. -. oiooiOcOor^u-jiooooooooiorro. S^ ^°§-^> >J °° > O fc. « o. 5o. 2. Oi«. O. fc>. >J. O. fe. «.

NO. 10. WATER TRANSPARENCY. Oi^ i-O NW'Ovq 1. co d\. K to to. o A N « w. *P <n -+. •?. o. oo'. r^.. K*. N. NN m NVON. to in ^d to uS in. to to to. vb "« pq. ofeNpq o. to "«. M. o. o. a. >..S. «Ph. tn. Ifl if). ooo. m«. o. 2. JOHNSON, DYER. >t V) >t\0. ifHO. N. 59. 00 ui. ir>. noo n 6 d d m m d\Chod. oo. to. PQ. — WILLIAMS,. to. «. pq. to. °°. "&. «. °. «. 2 ~ "^ %^>. V^.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 6o. Nf)K * N. NMD ^tOO m ^^ ooddodMNH^dooddooocodoHciddd. •SQ. ±-3. I. 1. .§. iO>fl. 01. IO. VO. P!. "?. Oiom«ioiOHOiflOfO'*OniOi-OulMNKOK10\N't. o. 5. VOL. 139. N. ^b. "<n. co. "V ~o. o. "oj. m. o. >3 "n So. "V "o. to. "V*. cq. o. vb "^ 00 "s. -. *"°. ^S. *2L. ffl.

NO. IO. tooo. 6. od. WATER TRANSPARENCY. f^>0 N N Is'O c dodiHOOMModddd fO. o. — WILLIAMS,. VO. if)VO. ifl. NC^ONr^m<NOtxOM -^too CO in t^OI « fn ro rn fO to M t n n to to to. JOHNSON, DYER. OMModoooodddd. * o coco oo •'too « Mfl m to to NtOtOtOtOtotOM N. t^^O tx. M. 01. ^MHNtOt0^f WU1°HMNlOtOTf W. 6l. >-i. *3. co^O Tt to to IO. HMNjOnTt WU »MHN. o. Q.

1. SMITHSONIAN MISCELLANEOUS COLLECTIONS. 62. VOL. I39. "to. uiiriintoiOioO^Oi^NnNin. 0\ lOOO 6 d\ 00 00 to fO CO. m. H<. m'. VO\O0)OOOC\OO nn n 10 10 ^f i- 't Nr. i. to <o ^t. m. 00 K. tx 10 10 <*. 01. VO. K. 0\0\ ,. ^HHfitoto^HHMnto -<t" ^. 1-). pq. pq o>. U. O PQ. o. Oh. .n c/}. pq. t^O O. rf to 10 WOOO Os to fO fO to N°. ^. 1. .555. a * o. 01. m m. ^r^o vovo ioir)to'^-Trtotoco. —. •3. IX. C<i. o». 1. W. ^tO00. ^^M O. u. -. i. O. Oh. tx. ioTrio-^-. h h n. nn.

WATER TRANSPARENCY. NO. 10. t^ao 00 00. Tt-. w w. Osoqiooo. rj-. >-<'. is. r-^. 63. iominfomui'1'N *o h h to4'o rt" i<otso 4 4 4 4 ro m cd iv.. up in to <^>. WILLIAMS, JOHNSON, DYER. -;. 1. :. i-<'. in. 10. in.. up. (ONiOHO|\ONKi-OflNMH'oin\ONN t'tnOO©-tf! iriMD NiniomwiiO'^OO'O oO N co ro n m m \0 O ^f "t 10 ui 10 >n m OWOi ,. l. »o. OJ. ,. \oOO. o. v->. *N 00. 4"o. \b "o CQ. ornNOoVoii. «00CQ O. trt. "w 00 **t CO. O. "o.. ao m o. Q. o. Q. M. Uo. w en. •I <u. 1. v-i. "n.

s. SMITHSONIAN MISCELLANEOUS COLLECTIONS. 64 •a. VOL. I39. -. 'tiOupupiorotoMvOoO TtcoupChOOCO 1. 2 « .£;=:. C4. >0. ifl. 10. m V) o. COCO^COrOfOCON. VOrorOroroMMOOO>oir)MfOlN.i-<i-iOOOOOt^OwNw. p-i. w. n nrf ^ m\o. vo. 5. ,—.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 65. o 00. n n tow m. \0 "O. lOO. JN.TfO» o 00 op 00 00 O K. 00 O ^T N op s 3-4CONMNoocO' ^-<3-MM01wNC -. -^f. cm. 1. >. J. ,:. -. 00 00 ^r. -. M. nann 1O00 00. i-h. tr>. M'. CM. N°. r-voq. (7. ^. CD rO. N. TJ-rf. ^--<T^'^-TtiOi-tp-ii-Hi-H'-ii-ci-ii-ii-iHi. )NNTt-OOO»O*NOi-iNNr'5C\t-^vO\£>r'5OOOO\0ir>N wO\w^TfOOOOO«^C N K K K l"^00 0000000000 0\OiO\OiO\CHOOi*^ 'tti01'f^if)>'l OOO v. ,. CX3. "o md *n 00 Ni-ys. "^00 o. \h. w. «>. Vo. vb 3.00. Nf"b. o'moo o. tb "n CQ. o^'niB o. S<. o. a. vo.

1. SMITHSONIAN MISCELLANEOUS COLLECTIONS. 66. VOL. I39. ^'MWl-ll-ll-lwl-IMIHI-Il-lWMI-IWWtHNNWfOCOr^rOCO. -e-a. &. Q. -si. O00rfi-ii-'O'*OO00>Of^MWO0000»ONNNiOtOVOt^t>.. «M. ovb«pq o. vb. 2. M. o^> «. pq. o. fc>. «. pq. o. 2. T ° m. 1—. J. ft.. CO pq. .2*. CO. s. h. fc. «. « V"b vb "^.

WATER TRANSPARENCY. NO. 10. — WILLIAMS,. JOHNSON, DYER. 10 miflmtri a m 10 »ooo «Owion Noooooooo n ixf^dodvd n oioooo n moo « d d d ^pooi n row M m w CO'<T'^r'^r t T'^-C^<r3fOC< t^tTlOlOtM i-i. T. r. cm'. 11. CM. i-i. >-,. 11. i-i. >-,. i-i. 6j. w i.;. \o d\. i-i. «10N( l«MOM OtNOOQN(1'0«NN«^ninoO'*NtOOOMN oo a a Oi a o\ onoo cooooooo aaO\ao\aa tto^to>fl'ti' t J'i')«toN l. l. ,. ,. 92.. ^. Q. S2. 0,. °0. 0>5 NO°. ". r. 1. ^. ^°°. "^. Q. ^>. °<. O. to. n. CO. Oto n. &. CM. CO. pq. o w CO. O. o. oo. ,. -too. cm. co.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 68. "cfl. So. 2. in in in in in m m M-oq "J 100 N c\MHHHHMHH'lOHMHM4(O(OC0^MN1-(iddl4!<iNN m « ~. .>q. 10 in 10 19 10 up >o. aw. VVVVVVV VVVV WHMH. 3.. 6. VOL. 139. ^~>. ~. V. &lO\bN°< to Oi««' ,''OiNI»fO\Ot(KltOOiiN» J. '.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 69. 00. po. NtiHHnddiifliiNNiofN'HMd. NNO00 Tf rf CO rj-. t}-. O. MD. N. O. \n. 00. v, CT5. "">. 1000 C\. *O00\OOTtN00O\O^rO>-iNOvOOiOO ^" t n to to\o uiTr^rmminwtt^N k "i m. N. to. m. 0C0. o. Q. <^°o. t. 0\0. <N. CO. to. O. o. Q. to. ^. °°. fO'O. CI CO 1-. O o. to. N.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 70 3. VOL. I39. •. •SO. »9oqroqvcqcqcsts.ioc5qoqioi-i^^ftxoo. »o. f. h. Sl.") irJ.10 i 10. 1-1. H. cm. m. fo *l^ m tN. p)m ^ tmv. £* cs. w N0° ° uiioiomvo KM3 O Nmm >0. ^-j. <n. 00 ^f. o. vb. "cm. 00. t t^N«N ir.oOCO m rr t. to in 00. 00. %r "b. co t-scc. ir, iri. r-^. 00 in 00 10 in. m. o>i woo'tovb «.

NO. 10. WATER TRANSPARENCY. aiiirf. — WILLIAMS,. d M m. ujn C} N. OOOOCOCO M O ION iO«i£HO O. N tH. is.00 oq uS 0\ C\. **3. w m. \o •<$. tj-. M M M. 10 H<. ^7^0 ix f? (N. N. o. 00. fN. t »o. JOHNSON, DYER. \o. oi. ion. mvo. TT. fooq \q oo. d. N. oo"«m "V'o o >j So Vd ^^00 to vb. o. Oi/>ONmONO\ O 1^ CO H M M. o o. ^. "<n. cq. ofe. CS. «mVo. o. 8. *. 3. >. 3 a CO. >. I to. I o. Q. to. ^. vd vd od oo. If). <2."r£?2. JI. 5. ^.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 72. VOL. 139. 5^. .Sq g.^. W. hoo^ovovooo tsinupuiup « * ^ 'd- -^ tt oi ro'J-iniow m m m m -w i-i-i-i w.ih. 00. co >o c\ d\. mMD o n- t^ i-x co co 00 >o ui^-ioiomiorrroc) n. o.. 3. *V). 00 "b. "V "o ©. Cb "w 00. "V "0. vb *w. o. na. ?9 10. m. rJ-O. 000. h. p-h'. ww*( CJN ^r. sr tt. <*3. v. \b. o. ____„oicocc'od 6 m n. n. 00. Vo. \o. n n. n. 00. <->. "t o. ui *m 00.

NO. 10. o o. cd 00. WATER TRANSPARENCY. d\o diM. is. noo o o\C\. ,:. — WILLIAMS,. i"'4-d d\ G\od 00. O OVOVO 0\0 0\0 Tf fOVO O (•5'ft (i t^O \0>0 C5N N 1010. t~-.tN.vo^O^O I^VO. "a's. V$ VsS s. °. *>. 2. ^ "&«. ©. 53. is.. JOHNSON, DYER. 00 00. m m. 2. 2 "jfs,. °. *>. 2. m. °. w. J3. u It!. o J3. H N. U. u ttJ. o. pq. o I-. ti. ta. I. a. O. J. a o. >o ix ci. NM3r0OiON"0iOOOC\O N N M CSVO^OVO^O t t MO C. to. &. H-f. -«. jS. a. w. ^. 2. O. 73. oi. MO. Vj tJ. ^ Y&. n. °. -tf-. *>.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 74 73. .. •5Q ci. 00 *© ^f. 7n 00. 1. VOL. 139. Vo. w « '. ot. ofew. t^ t^ rt. 00. Vo. m m. o. -4. oi. ". tb. N. °°. oi. cm. Vo. n w. o. m'. "+. to Vi 00. 6. c\. w *. V*b c. ej. c>i. to Vi 00. w. V.

NO. 10. WATER TRANSPARENCY. Ncocomin. o\ co. cr>. <? 10. — WILLIAMS,. m. **•. ts 10 f?. w. n. fj. JOHNSON, DYER. U?'T. ^oq. Q. 75. "?. <-^. cooooo^NOOfoomM^iooo^nMooonoinONintiNOB to^o ^O m m ^ tvo ^o 10 in t ^^O vo m in m (^ m\o inmrftoinmwM'tn. o. V"° O. 00 vb *N Mi-iCtc«5. "Vt*b Ofo^OO "V*b 00 Vb Ovn 3 NOO i-it-iO<ro wiHMco^ '-iwWrO^-. vft so "<N. >. o. ON. ^. 2. 6'. o. Q. Q. vo "n 00 \j-*br i-ii-HNf 3.

1. SMITHSONIAN MISCELLANEOUS COLLECTIONS. 76 •3. VOL. I39. •. 3Q. mm dod. o>. N,. po f). n kvo 00. m. m v) to Oi. m d n 6 Tt-d. CK (M. Tf. "5. 00. N. «. ^. 00 to 'p. Kg. nV. h-l. n. ^. 3. •. .sfz;. in. woo. tovo. WCO. f. o. I. „. "?. /\. h 00 N> p m 0) w. rf w »^ ^>HA1-I 1. 28. r^{^ t. l. I. A. § + X A. .. mm °°00. "^ m K N «h d 2 AA >—. I. hi. U). ^^. I—. 1-1. o,.

WATER TRANSPARENCY. NO. 10. M. M. «>. TtO. t^. Tl-. 6. o\. 4. c\vo*. to to. 'fr. in. o. co i. <=*. I. n T. o. rr co. 7/. A i. !. 4-. 2. 3. i-i. M M. °? °?. w w. A. toco. 5. -+*. hn. JOHNSON, DYER. 77. I. **•. -+». vo. noocococooomm^noo *Vj-"b. o O O. lO. — WILLIAMS,. oo tn "n So. "V*b So. oo oo. w-,.

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WATER TRANSPARENCY. NO. 10. — WILLIAMS, I. h-t. t-t. t-tO. •-(. (-H. l-H. t-H. n>-^>-t»-<. I—. .I-HI-.A. -<. g^ASAAAAAAAAi N:S" "",. ,. ,. I. >-,. ^-t. '.». Tf. AA. I. JOHNSON, DYER. I. w w cq ioOOMKhhhOiK MH,riu,u,M ". V0,o. ^. + + + + + + + +8 »H« OvOOOOOOOOwt^^W O^OOOOOO""10 &* n. -*,. '. f>. -'-. Cn. :>.. woo -toro w. oo \r. o^, woo ^ooooooooooooon, woo wrx woo w o. iri. co rQ. 79.

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NO. 10. oo. m. 10. WATER TRANSPARENCY. a*. h. N. in o> in 10. fN. — WILLIAMS,. fj. 't. N. 0\. m. JOHNSON, DYER. M N. rn. o. 8l. <-<. •-•IHPIPlhHI-ICVIpit-ll-lttCll-ll-ll-ll-ll-ll-lNNl-lMI-lCICll-lVO. vo to t^ t^^o \n. <2 "frfe. g. ts.. °2 *Sffe. t-xvo. 2. "i in t^vo vo vo vo vo vo. =2 "&*>. 2. ^2. *&*>. «. °S. tv.. Rvo. "fr^ 2. <£. vo. *&*> 2. % 1f%. o. 8 O. I. \b.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 82. VOL. 139. SQ. •sq. 10. tn fjoo 00 00 00. o 000000000. m in 10 10. n >n m in in m n n n n n noo in moo a m a m MO(«5«conTi-^<t't't^tininH. On 00 00 00 00 00 tn. &S. o\. &. «. >-.. 1-1. 01. en en. 8. 00. •. s S. o>. m. m N r^-in.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. 83. m flNNNNKNKNIsOONNNNNNNN 10 10. CO CO f*300. JOHNSON, DYER. ir>. 10 in. to. ^I-TJ-TJ-TJ-IOVOVO vrjvoco O\0Q O O OCOCOOOCOOOOOCO O C\ O Q O O Q o Q Q Ovoo oococooooococooo oi&oiaawOiOi ooioo>ooicio\oic>c\o>o\». "01. 00. "t"b ^b 3.00. -<i-*b. vb. "<n. 00. o. r>i "<n. 00. 'to. vb. "o). 00. Vo. \b. "<n. 00. o. •8. 1 -a. c 3. 8. c o. to. 2. U. «. tr>. "^ 00 Ni- "b.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 84. co. •5R. 10. !>> CO. :. fi. s. PS. <. 0). u"5C\tx'3-fx QQOQOC5 a^o^o 'o t^oooo a& o\ o\. to >j 00 "Vj-*b. "a. io »o. KOO d^-6" lN'O00HM00HHn0000IX)00>O>')iO N N N voMD VO -^Tl-^-q-Ta-Ti-Tj--^ CO CJ Tf "t 3 -JTrr TfH m ti. p-13. VOL. 139. o. -rr ir) ""). o\0\0\aoioao»ao\oo\oo. to "« °° S"*b vd "w 00 "V*b md. noo o. to "n 00. Vo. vb. *"n.

NO. 10. "b ^O io^'O t Vf. 00. WATER TRANSPARENCY. "*M CO t>» t>». o. trt ""N. OO. i-c. 1-1. *"* en. "b M3. n n t 00t "(N. — WILLIAMS,. "Vj-. "b vb "N 00. "5\o. o. tN.tN.. a. PQ. 3. JOHNSON, DYER. 00 *rf *b MD "en So Nt *b vb <n *N 1-1 11 on to <o 't ^- iri'O »o. vl-'. 85.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 86. +. =Q. .Cq p., A. £00. o. W.^. N N Nj.^. m T T(. "h So is. t>». 1. VOL. 139. j.. o. T;. ^. th. ion to. T;t. So w m w. iO LOCO CO .^ T T:f ^. <N T). . ). f.. .. ). 00. <-<. h. 00. Tj.vo^OvO. low. V "6 vb "n VoVO vb "n So o rx^ "m So 01. CO CO ^T lo. >0. l>. l-x. iri. N C^CO OJ uots.CS « W CO 00 00 COW CS cococO't-'T'^T-'tf-iO. t-i. h-i. "Vj-. N. "b vo "« oo "V *b CO CO. ->t. -<r. IO v£>. o w.

NO. 10. CO. 00°. WATER TRANSPARENCY. woOOO io»T)iO»r)N M. ir>. lOOO. 1-1. — WILLIAMS,. m. JOHNSON, DYER. 00 00 00 CO h-iCOOO "100. w. 87. M N N ts.. rO 10 vo K. tx\0 "S tt. ^TrrONMMiHMwOQi-ii-in<r2<r5C «N<N<Nf^MMtHMrOwi-ii-iO OCO oaoo\o\o\o\»o>o&o\ao\0\ao>c\o&o\OM>o>o oco co co co k k v. r. "(N. So. 'to. "o. *oi. So. "Vb. "b >< 00. o. rh *W 5o. "Vb. vb. "cs. co. Vo. \o. ~<n. o. a re. re. >>. m I. E o. u I. 6 o. 2. *a3. ^o. *<n. So. Vo.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 88. •So. ^. ^•j=. MS. ONN ON oO O O 0\ O\00. 00. o. v—/. ^x "h 00. N NOOOOOOCO. wvoo. N fONOO m. i-. CO. VOL. 139. NNCOOOOOOO. O o. 0\ Oi. "V "b. vd "w 00. "V "6. md. ~<n. co. o. m "m. 00. Vo to. «. co. V o >b. "Vj.

WATER TRANSPARENCY. NO. 10. IX. 04. 04. 10. 1/-J00. 00 00 00 00 u->00 00 *0. >-i. — WILLIAMS,. 04. 04. 04. 0). JOHNSON, DYER. 89. T «h t. N N N N. 04. T. •'T. 04. 01. 04. 4XOOi-iw0404040404>-i0404TfioOQQQQ'-iOQQQQOOO*.Or'3tx. 00. O. to. <». 00. *. O. \0. 04. 00. *. Q. VO 0)00. O. Tr~,. 0400. *OO. 0100. t. O. vO 0)00. oto. %. a o. §. 5 u. x. p. 04.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 90. VOL. 139. •3. NNNN. a. 3. »V*OfQ o tb. "*. w. "". °° CQ. o. to. N. °°. jo ^o. "siPfi.. "^""S vb "w So. O. NN. o. to. a ">\2,. •I. f3. £ K. 5. c o. "«.

NO. 10. WATER TRANSPARENCY. N M° M M N in O OJ N>OVO O in^OOO m Mto^toto'O^T'fiOi'lH 1-1. t-i. vo\o inmvo. *to n aoa go\a o\ «:. 00000000000000. 00. "Vo. ^o "n 00. Vpii. nco o. — WILLIAMS,. JOHNSON, DYER. mciNNNroro tN.N ih. O. fi Ci. 10 10. N "ON NMOO ts.in N N N rotOtO'tit'tOO. 0\ 00 CO 00 Ov b». N. C*J. 0). m^io^fON n n roromt-xoo go\ no\ woo i^O vovooooooooooooooooooooooo O\oo m\o. \h. "^. mV oi. 91. w. co. in.. 00. "V*b ^> *n 90 %r"o vb "w co o \a.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 92 •3. VOL.. 1. 39. .. — M. "v d> \^j v^ n cj 00 in «t0(0fOtO<O(Ot0n •rfVO. ri \-v i»rs. *-^ vy to to r^\. #vs. ».•«. *^\. *^n. <rj. #***. r*j r«i «->. 10 wi i*\. **-i. 000000000000000000. •. »^-. •. kmN 00mN. r>. * "h. oi yi. t^. \^*/. _. N 00 MOOOO N N N vd md •** •<r n cin-t ^rvo tt <*• o ra n ra. 00'. ra. •"*•. C\ 0\ C\ 1^00 co 00 00 00 00. Oioao\ao\oa. at. O.. *<N. 00 Nj- "b MD. "<M. 00. "rj-. *b ^> *N 00. oth^OO. -<fr. "b *0. N. 00. t O ^O. 04. o. Q. '5>>. 13. m U. c. .2. m. c pq. fin. pq. HI.

NO. 10. 01. m. o\. a. WATER TRANSPARENCY. (H. 00 00 00 cjoo. h. 00. <-<. \o. — WILLIAMS,. mHMM. moo. >-i. JOHNSON, DYER. w. WIN 00 00 00. ro^ei. -r. i-i. tN. fO fO. tt. 10*0*0. NN. CO. 8. t-l. «0. in. C/3. > o. o. c. «. 6 a,. a. U. s §. u. 10. 00 m. N (M 0) O N rOTfinrfH « -t t ro PI <OiO<OVOM O\t^"0 tO O O O\0\O ON O\00 00 0\0\0\0\OnO\OnC*CnC^O\C\^0\0\CNGnO\0\0>0\C\ t^OO 00 00. w. 93. m -«.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 94 =Q. rj-. 1. ?. 1. c«. "PT3. W2. a c. 1. 39. $. K sG N K n OS T ^ W n n r. VOL.. t)-. O n. 10 >0 •*}. -^-. aa a. M -rj-. f^. t. mooOO. tr> -rr. mm 1-1. miomw. 00 00 CO 00 00 m w w loiommvo^o^o w m *n\o. hOOOO *n. 1-1.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 95. oT. oo t-^og i-noooo. rod n n ... ^PHOinioioifiiOV) t^n«nn « io h h m h m h <M. 0). 00. N. o. to. 00 00 intl to 00. >-i. t-t. AAAAAA. VSfc 8 &fc. °. *>. 2. °2. W&^"&J3 £ fcfc& o o. 00. «. 50. %j to to to oo. V.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 96. 3. VOL. 139. •. en. "5H 00000000 ,<=•(/). VO VO CO 00. r^t^t^r^w N K K N^O. >-•. m w w w w ixt^cood n 6 dvd\rod\^d w O t^J^OO N M 01 w m to n N N. VO VO VO ^O ^O. SO. i-.S. O\0nO\0nC^0\OvO0\0\C\0\^0n0\O\0nC^C0. k. k\o\oco. 00 00. nm. w-,. l"^. as. a. *6 vb. *"«. oo. o. to "w oo. "Vt. "b vb *w oo Nj- *b vb. moo otn. Q. s. I. y. w o. "*. o. «. cc.

NO. 10. n. in. WATER TRANSPARENCY. **>. \*j t*i. rs. t^ t^ o,. «. ix» i-s. *. — WILLIAMS,. \-j. v*. '^ rf 0) N K.0O * rfOOO OOO O P> w (M i-<>-iC\|NN<NNNN0JC)C3CO01>-ii-<>-ii-i <T>. 3. 4. tJ-. inn. >0. rf to -t^ 00 CO 00 "I" 00 N NKKNNKKKOOOOOOOO -. ). ^. MOO m 1-1. cj. ^. O. M o. 5. ffi. ^5. 3. rt. C o S u. bo bo. W. •*}. tO'Oco NT. So. '5b bo. t}-. 00 1^. f*i. ui «^ ^\ u) C> 0\. i>». 97. t^. N dO w N N M NMNMhmhMmNpicin. vd. N 0) 10 O O iniO^O^DOO. 01. JOHNSON, DYER. bo. § It!. O. KN. ro Tt>nrl-Tt. -<t 00 NvO VOVO l^t^t^l>.t^t^. C^OO i-i. oi. i-i. On. Ov. "I". O \o ^ «. N. <N. Tt-QvO N MOO iO\0\0 ^T. T. l^.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 98 73. .. 1000. i. •o^. >;^. 1). Si. ir>. w) in. mm. in. mco. NKo^tor^iotNr>.K.o\NNvN o *. 000 ©co. O. "9. v>> '*->. onco t^vo t^co. i. 00 00 co 00 00 00. ™ m. °0 1-1. S"OVD cq m to. t CO^. £>. OS. 00. ^f. O. O ©. ir>vO t^. •££. so. io\0 \o. 0) r^.. otr, VD. Tf. S. 5. u. ca. 1. 5 g. o Uh. *n ei c*i. ro>o<o. lOVO Os. O. OsOsi-^l^I^J^txt^CO. s s. £3 CO. VOL. I39. N m. *. w-4 n n. ro. too. o\. t^ CO vrjVO r~* W tTi l^ l>. t^. t^ tx CO CO.

NO. 10. ci\oo i_(. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. r^i^ts.t^.K.K.dvO c* d\ b\ oo 10 md m w w « m m m oo m oo oo mo ^b -^ M i- t-ii-ii-iC <i-i>-i'-ii-iw\OiOVOVO\OiOir)VO Ot-^>-iOOi-c>-ii-i»<-<. i_ii-(i-i. 1. 1. >. A co. o. inn n. \b. Bo. ^r. •«*. %t ~o. <*•. tj-oo. vb "n oo. o. £). oo. aaooo\ciOiOiO\0\o. ** *b vb "n So ?h "n oo. m. 'V "b v3 *n o to. 00. *. CO. "b o. 3. 3. %. pq. ^ U. >-<. io M o t|-m o\^o *o vo »o. iOTfin«>ioci(«)ininNoco. o. ^t. A. oo o\oo tx. "V "b "b. |. cq. r^. 99. a cd. § £ V3. "n So. "V.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 100. VOL. I39. 2Q. <«. •3R. 4 « m w m tN.r'bfoiood w koh m HMHMMHMHtOCOt^^NNMMMINWMOfNMMMNN. \n. ci. c:. fi. 04. oi. ^t-. -s-. rt-. -^j-. oi. >*. Kg. p.. I. <. "00 otb woo. Vo. ofe «oo. V°. vb. 'noo. Vo. vb "w. o. w is « I/!. 5. u. °s. I PQ. W. CO pq. c rt. CO. tn "n 00. Vo.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. NKNN. NflUKOtllO'Oi'). tON. 101. CO. AAAA + oooONoNc*3t^moooocNOO\o\C\0\ o\oo oo i^cc oooo>-<oi-iot^Tfco t^ 00 KCO CO 00 OO M O O O O oa»0\0\O0\0\OaNtsN0000C000 t^t^tN.. "o if)\0*0 UtT oo t "V. vb. "in. vo. "in oo Is. t>«. o O. *"* to "n w So ih. ^. ct. o. (^. o "nrr oo>T Nt"b ^b Ti^O vo (<). ~<n t>». oo I-n. o lO. "d. 5. a. PQ. pq. 3 Ih. <U. B. w. s. ^. to. "^ So >-i. >-i. "Vf CM. o. \b "« bo. Nr. roro-^-Trvrj.

SMITHSONIAN MISCELLANEOUS COLLECTIONS. 102 "3. VOL. I39. •. q mis r-,„. m. osco co d\Pi. io«. O O « «0 Ms O. "- "Vj. cy.. o). ooioin otrit^o. c*}. fi. tncc. ctodco. w. o. io^nknnnnn »o 00. m'. fb. -<i-. "<r. tj-. tj-. *r. as. CO. 00 ~^r "o sb *n 00. "V *b. so. "<n. qn, noo "V ~o. % ^. s a. .5. afe. £ I. I. •££ CO. PQ. c p to. >>. PQ. U. So. "cm. 00. "V.

NO. 10. WATER TRANSPARENCY. — WILLIAMS,. JOHNSON, DYER. 103. t>t-Ntv.tN.q Ttoqoqcqi-j^t-oq loujioupioinfoiriiri cq ?o c© cq is. is. "} "«} ^j- omdo co cd ^r ^t* -^ "S "i \o 00 d\ b c\ ci cd 00 ONC^t^.N.N.tv.ts.o\foovfi 1-1. ^. MM^Oi-ii-itHMi-ii-iMi-iiH. 5S^n ^h^. °. <>. 2. 'S. "ft. to to fO to f^. °. ^. 2. %«. o. ^. 2. %«. o. o. 3. cr. B. I. D-. it!. H. O. 3 o. PQ. E u. (A. B. o PL,. 1-1. o*«« "**o % q.<». •a. 55. N N.