mountain observatories

Sir William Herschel was the first to consider the observer as part of the apparatus. In the paragraphs that immediately follow, I have given brief accounts of the most important steps in the evolution of the idea of the.

6 MOUNTAIN OBSERVATORIES IN AJUERICA AND EUROPE

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 1

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In the telescope, and especially in the spectroscope, they are very obvious and sometimes quite fatal for measurements. The study of observation conditions at mountain observatories thus becomes of paramount importance.

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High-level meteorological observatories will always be necessary, despite the fact that their records are necessarily greatly influenced by merely local conditions. The great apparent waste of money in the establishment of new observatories in the United States may be partly accounted for by the fact that most of them are attached to colleges, and are directly useful in training students in exact methods.

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MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 15 less perfect conditions, If one is searching for the site for a new

THE OBSEEVATORIES OF EUROPE

Professor Smyth refers to the unusual dryness of the air at high stations as an "agent which produces good definition." The upper part. A strong wind was blowing the smoke from the great crater (which rose behind the observatory to an elevation of 3,312 m., 10,866 ft.) away (from the direction of the sun.

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Janssen's Expedition to the Summit of Mont Blanc (1890).*

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 23 as it would go and kept two turns of the forward line wound round its handle

WEATHER ON MT. BLANC

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Bigourdan has determined the force of gravity at Chamounix and

The problem of building on top of high mountains is then a good solution, and M. 34;actuelllement siimportantes pourles progres delaMeteorologie et de rAstronomic," are open to occupation as soon as we have learned to place buildings and instruments on them, which are appropriate to the conditions they will be exposed to.Blanc station has not yet been written, and it is at least possible that the very ingenious arrangements for the foundations of the summit station,.

Simony in 1888 on the summit of Tenerife, which aimed to record the solar spectrum by photography and which influenced observations to be made on Mt. It is important to know what the limits of the solar spectrum are and, on the other hand, constitute the observation of these limits at different altitudes.

PROPOSED RAILWAY TO THE SUMMIT OF MT. BLANC

THE METEOROLOGICAL OBSERVATORY ON BEN NEVIS (4368 FEET)

THE METEOROLOGICAL OBSERVATORY OF THE SANTIS (8200 FEET)

THE METEOROLOGICAL OBSERVATORY ON THE SONNBLIOK (9843 FEET)

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 33 There is eight times as much snowfall as rainfall at this station

CHAPTER IL— THE OBSERVATORIES OF SOUTH AMERICA

36 MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE

Professor Schaeberle and a native reached Little Chachani, a peak two or three thousand feet below the main summit, while the others prostrated themselves with mountain sickness. 34; Although the character of the images was less favorable than at Arequipa, the curious feature of the very active commotion in the constellation without any accompanying blurring, and the diffraction rings, appeared much the same as at the observatory below. The next day Professor Bailey was obliged to abandon the ascent at about the same height.

The Indian guides did not suffer from cold or mountain sickness at all; them free. He believes that it will always be impossible for observers to live and work at these high altitudes.

38 MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE

It meant that 'the brilliance in the sky was much clearer than it is now, and that 'the brilliance in the sky was much more pronounced than it is now. Mount Hamilton in favorable weather." Through the kindness of Professor Bailey, who had charge of the observatory, opportunities were given for the visual use of the 13-inch equatorial. Professor Schaeberle (Eclipse-ReportofApril, 1893, p. 21) notes noted that "the brighter stars were surrounded by many well-defined diffraction rings," which seemed unaffected by the apparently great commotion in the stellar disk and jets - a curious kind of rapid twinkle without blurring.

Turning to face the moon, I noticed that the sight was 'woolly', the effect of small atmospheric waves clearly visible in the slight movements of the moon's surface. Douglass, one of the astronomers of the Arequipa observatory, has a few sentences relating to the conditions affecting the sight there in the American Meteorological Journal (vol. A comparison of the results of observation at the three places is difficult to make many accounts.

It is of great importance to obtain a definite idea of the relative excellence of observing stations in different parts of the world.

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MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 43 high to low pressures it certainly would liave been of no service in his

THE OBSERVATORIES OF NORTH

AMERICA

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. !5

Su Coast and Geodetic Survey Station, Sherman, Wyoming

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 4T

4S MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE

An inspection of the numerous plans and projects submitted to the Lek Trustees during the years 1874 onwards would show more clearly than any other process how little was generally known at the time of the conditions involved in the selection of a site for a mountain had to apply. The long legal and other delays in building the Lek observatory were very expensive, but their compensation was obtained in the opportunity for a thorough discussion of all details. The final result was absolutely free of errors of commission; and the omission was repaired as far as available funds permitted.

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Professor Grreene finds that the species of trees, etc., on Mount Hamilton are almost always those of the arid interior of the State and not those of the coastal regions, and that the botanical region is more closely related to the arid San Bernardino Mountains than to the peaks from the coastal areas that are very far away. closer. When none of these obstacles are apparent, that is to say for a very large part of the days, the atmosphere is very pure. First of all, the topographical situation of the observatory, surrounded on all sides by steep slopes.

Secondly, the slopes immediately surrounding the plateau are composed of fragments of bare rock, which become strongly heated during the day and whose radiation seriously affects vision. A considerable amount of water is needed in our excessively dry and long summer to prevent common grass from dying of drought, and sufficient water has not been available for this purpose.

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The sight is usually stable throughout the summer, and on many days it is remarkable. In search of a reason for the excellent visual conditions that . })revail liere in the summer nights, it seemed to me to be largely due to the banks of fog which lie over the Santa Clara valley. There is no doubt that our best nights usually follow days when the fog has blanketed the valleys (although there are exceptions).

There is no doubt whatever that when we can see the electric lights of San Jose some eight miles away and 4,000 feet below us (and therefore when there is no fog), the nights are usually not first class. I still think they are the most important factor; but an experience of actual residence during the years 1888-1896 has proved all this to us. When the lights of San Jose are visible, they are usually very unstable, as would be expected, and the vision on Mount Hamilton is usually not good, as I said.

However, there are instances where the San Jose lights appear quite stable and are still clearly visible; and on such occasions the view of Mount Hamilton is usually good, although the beidora is perfect.

SUMMARY OF RAINFALL AND TEMPERATURE OBSERVATIONS FROM SEPTEMBER, 1880, TO NOVEMBER, 1893, INCLUSIVE, AT THE LICK

Detection of very faint stars: Professor Schaeberle's and my observations of the stars in the Lyra nebula, f and Professor Barnard of the stars of Orion's trapezium show stars of the last degree of faintness. Observations of faint satellites: The faint satellites of Mars are observed here as light objects. They were discovered with the 36-inch equatorial, and two of them (D and E) were seen, I believe, at no other observatory.

Determination of the surface features of the planets Mars^ Jupiter^ and Saturn : a long series of drawings of these planets by Mr. The bright projections on the terminator were first discovered and measured by the 36-inch telescope§§ and a fine division of the outer ring of Sa - turn, discovered by Professor Keeler in 1888, was not discovered elsewhere.|l|. Nothing can be more satisfying than observing the phases of the eclipses of Jupiter's satellites, which were regularly observed here for the first time. It.

FIGURE i.S.- — 'MT. WHITNEY {14,900 feet), FROM THE WEST.

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 57 Markings on the discs of Jupiter s satellites have been systematically

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Much of it was close to the upper one, and in full view of it. No point east of the Sierras has the same advantages for the particular (solar) work referred to. Many stations in the Sierras and in other areas of California and neighboring states are perfectly suitable, but as Mount Whitney was the highest and most southerly of the great peaks, it was chosen.

Langley, assisted by a committee of the National Academy of Sciences, the United States Congress set aside for sale a significant area, including the summit and environs of Mount Boyden, to assist in the establishment of an observatory' such a height that it would be free,' as far as possible, from obstructions. As this was for many years the highest meteorological station in the world (Leh, Ladakh at 11,503 feet, the Sonnblick at 9843 feet), it will be interesting to give a brief summary of the various tables.

First, it is well to note that the station was continuously occupied for fifteen years, from October to September 1888.

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 63 their expedition is interesting on many accounts, and it is especially so

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These statistics obviously refer to California's dry season, with the months of December through April being much less favorable. it is clear that the number of clear nights on Echo Mountain is very large. larger than any observation station east of the Sierra Nevada. My impression of the constellations is that there is more dancing and shooting with small arms than at lower altitudes, but less blurring. It is well known that the transparency of the atmosphere around Denver is remarkable, and Professor Howe refers to it.

On March 5, 1896, I addressed a letter to Director Anguino asking for data regarding the stability of constellations on Tacubaya, based on. With regard to the second question, the problem is complicated for us, not only because of the altitude, but because there is a local cause that perhaps has a greater influence on the photographic images - that is, the movement of the dust that constantly rises in Mexico's waU.

USES OF BALLOONS AND

KITES

68 MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE, The balloon used by M. Hermite was made of goldbeater's skin

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 69

During the scientific balloon ascents from Munich, the neighboring mountain stations of Hohenpeissenberg, Hirscliberg and Wenclelstein. corresponding observations made on many separate occasions. The compilation of all these showed that the mountain temperatures were generally far from harmonizing with the temperature of the free air as obtained from the balloon. This can only be obtained from the thermometer readings at the high level stations by applying empirical connections which are neither constant nor certain. Further progress in scientific meteorology therefore appears to be dependent on data obtained from a series of intelligently planned balloon ascents, and this conclusion is gaining ground among meteorologists.

Their observations must in many cases be supplemented by records made in balloons, and in many cases it seems desirable to abolish stations altogether and depend solely on balloons. However, balloon ascents can be made from any chosen location, and . this represents a very important scientific advantage. The conclusions here very briefly formulated as to the comparative advantage of balloons over mountain observatories apply also to observations made from kites, of which an Avord will be said.

Wherever strong winds blow, this survey method promises to be as useful as it is simple and inexpensive, and with skill kites can be raised to the upper winds through almost dead calm winds.

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE. 71 comes too heavy to be lifted, and the method of using kites in tandem

Burnham (S. W.): Report to the Trustees of the James Lick Trust Of Observations made on Mt.Hamilton, with reference to the location of the Lick Observatory.

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Naval Observatory during a month's stay in Colorado 1873, with special reference to the constancy and clearness of vision at altitudes from 6,000 to 14,000 feet in the Rocky Mountains.] 1873. Paper on a branch of the Naval Observatory west of the Mississippi of the Public Ministry of Mississippi River. Instruction etc.

MOUNTAIN OBSERVATORIES IN AMERICA AND EUROPE