796 REPORT— 1895. 



From these tides, checked by comparison with those at other parts of the 

 coast, the author has formulated a table showing the amount to be added to or 

 deducted from the height ot' tiie tide of the day as given in tlie tide tables, accord- 

 ing to the strength and direction of the wind : — 



Approximately it may be taken that with a given force of wind of 3 on the 

 Beaufort scale a tide will be raised or depressed by half an inch for every foot of 

 range ; with a force of from 4 to 6 the variation may be expected to be 1 inch 

 for every foot ; with a gale of from 7 to 8, H inch ; and if the gale increases to 10, 

 then L' inches. For example, supposing the rise of a Spring tide at any particular 

 port to be IG feet above low water, and the wind to be blowing with a force of 5, 

 then 16 multiplied by one inch would make that tide 16 inches higher, or 17 feet 

 4 inches. 



It is not intended that any absolute reliance can be placed on the formula, but 

 that it may be taken as a sufficiently approximate guide by which pilots or cap- 

 tains of coastiug vessels may be able to form some estimate as to the extent to 

 which the tide will be atfected, and consequently the depth of water available 

 over bars or shoals. 



FRIDAY, SEPTEMBER l!). 



The following Papers were read : — ■ 



1. Notes on Autumn Floods of 1894. 

 By G. J. Symons, F.R.ti. 



2. On Weirs in Rivers. 

 By R. C. Napier, and F. G. M. Stoxey. 



3. An Experiment in Organ-blowing. 

 By W. Anderson, C.B., D.C.L., F.R.S. 



An organ of sixty-one stops and four manuals at the Goldsmiths' Technical 

 and Recreation Institute, New Cross, London, was found defective in its blowing 

 apparatus. Sir Frederick Bramwell, Bart., LL.D., F.R.S., and the author, governors 

 •of the Institute, were requested to look into the matter, and finding that the 

 maximum pressure required was only 10 inches of water, determined to adopt an 

 ordinary smiths' fan, driven by an electric motor specially wound and coupled 

 direct to the fan spindle. Some preliminary experiments showed that a fan with 

 a 10-inch outlet and a six bladed 25-incli impeller, driven at about 1,900 revolu- 

 tions per minute, was amply competent to give the pressure and volume of wind 

 required. Some apprehension was felt lest the pulses due to the fan might 

 interfere with the lower notes of the organ, but exhaustive trials have shown that 

 no such interference takes place. 



4. The Groivth of the Port of Harwich. By W. Birt. 



5. The new Outlet of the River Maas at the Hook of Holland, and the 

 Imj)rovement of the Scheur Branch up to Rotterdani . By L. F. Vernon 

 Harcourt, M.A., M.Inst.C.E. 



The gradual shoaling of the mouths of the Maas, coupled with the increasing 

 draught given to sea-going vessels, rendered the access to Rotterdam inadequate in 

 the first half of this century. An attempt was made to obtain a deeper entrance 



