Victorian Institute of Engineers.
(ESTABLISHED 1883..,
1907, SEPTEMBER
4TH.PROCEEDINGS.
The ordinary general meeting was held at the rooms on Wed- nesday, September 4th, at 8 p.m. The President, Professor W.
C. Kernot, occupied the chair.
The minutes of the August meeting were confirmed.
The discussion on Mr. T. W. Fowler's paper, `The Naviga- tion Problem at the Murray Mouth," was resumed. After it had been continued for some time the PRESIDENT announced that al- though he had intended to speak on the matter it would, from con- siderations of the available time, be necessary to proceed to the next business.
The PRESIDENT then gave a short lecture upon "Balloons and Air Ships," dealing with the subject historically and generally and illustrating his remarks by many lantern yews.
Mr. JA s. ALEX. SMITH, who acted as Chairman during the lec- ture, said that time would not permit them to dwell upon the matter which Professor Kernot had brought before them, or to discuss it, but before proceeding to the next business, he thought the lecturer was entitled to receive their hearty thanks for his contribution. A cordial vote of thanks was duly passed.
The PRESIDENT, after responding, called upon Mr. ANKETELL HENDERSON, a visitor and a member of the Royal Victorian In- stitute of Architects, to read his paper on "Building Regula- tions."
Mr. ANKETELL HENDERSON said his own society, the Royal Victorian Institute of Architects, prepared a syl- labus at the beginning of each year. It had, therefore, not been found possible to present the paper before that In- stitute. As he considered the question one of present importance he had requested permission to place his views before the Institute of Engineers, and now thanked the Council for the opportunity which had been afforded him to do so.
54 VICTORIAN INSTITUTE OF ENGINEERS :
After the paper had been read the PRESIDENT tendered the thanks of the Institute to Mr. Henderson for his extremely useful communication.
Mr. A. HENDERSON brieny thanked the Institute for its appre- ciation.
The PRESIDENT announced that the discussion would be de- ferred until the next meeting.
At 10.30 p.m. the meeting closed.
DISCUSSION.
THE NAVIGATION PROBLEM AT THE MURRAY MOUTH.
Mr. FOWLER said that before the discussion upon his paper was resumed he desired, in view of Mr. A. F. Smith's reference to the harbour works at Durban, S. Africa, to place some informa- tion being a paper by Mr. C. W. iviethven, M. Inst. C.E., on "The Harbours of S. Africa" ; published in the Proceedings Inst. C.E., vol. 166. Mr. Methven had professional charge of the Durban harbour works from 1888 to 1895, and hence has intimate know- ledge of the work. The following extracts were from his paper, p.
32 :—"Durban harbour is a lagoon harbour of a somewhat similar class to those of Malamocco (Venice) and Karachi. The lagoon, which provides a large and valuable backwater, is about 72 square miles in area." P. 33: "The rise of the tide at spring is 6 feet;
and the tidal volume available for the purposes of tidal scour in assisting to keep the port open, was calculated from the detailed survey made by the author in 1892, to be about 28,327,972 cubic yards. Since then dredging operations, where they have removed material above the level of low water, have somewhat increased this. The range of tide at neaps is not more than 3 feet, and occasionally only 9 inches to i foot. The tidal volume, therefore, during these tides is very much less than during spring, and the most valuable period of scour is during the first half of the ebb-tide of both springs and neaps, as after that there is little tidal water left to run out beyond what is contained in the channels." Further on (page 41), after giving particulars as to dredging and average depth on the Durban bar at low water at various times, Mr.
Methven wrote : "But the increase of depth in 1904, after the com- pletion of the north pier in 1900, was about 381- per cent., namely from 18 feet 7 inches to 25 feet 9 inches at low water. This splendid result is undoubtedly due to the proper training and in- crease of the tidal scour, coupled with the dredging operations."
Mr. Methven does not state the width between the training walls at Durban, but by scale he shows it as about 7.50 feet. It will be noticed from the above that Mr. Methven does not agree with
