FOR THE ADVANCEMENT OF SCIENCE. 123 



rises ; the weather is then generally unsettled, with high winds ; as 

 the weather settles, it not unfrequently remains in an indeterminate 

 state. These variations apply to all the changes of the moon. 



Mr. Ettrick read three papers ; the first on an instrument for ob- 

 serving Terrestrial Magnetism — on improved Rubbers for Electrical 

 Machines — and on a new Instrument for trying the Effect of Elec- 

 trical Discharges in Rarefied Air, or in different kinds of Gases. 



Mr. Adams, in a paper on the vibration of belis, endeavoured to 

 explain a peculiar beat frequently heard in the sound of a clock or 

 tower bell, which he considers to arise from unequal thickness of 

 the metal ; this he illustrated by some striking experiments on a 

 glass bell. An interesting conversation then took place, in which 

 Professor Stevelly, Professor Forbes, and Mr. Adams took part. 



Friday. — The papers read this day were by Mr. Whewell, on a 

 new Anomometer. In this communication Mr. W. explained a 

 method of tracing or registering the course of the winds through a 

 given period by the motion of a pencil, on an appropriate scale, so 

 as to obtain eventually a true type of the winds, which has never 

 yet been arrived at by other instruments. 



Sir D. Brewster read a paper describing a contrivance by which 

 he was enabled to render distinct the dark lines of the spectrum 

 under the most unfavourable circumstances, and obtain other useful 

 effects. The method was to introduce a cylindrical refractor be- 

 tween the eye and the eye-glass of the telescope, the effect being, as 

 he shewed, to give a linear form to most irregular images. 



Dr. Hare explained many interesting phenomena attendant on 

 the electric spark and the divergence of electrified bodies. 



Mr. Hodgkinson read an Account of some Experiments, at the 

 request of the Association, to determine the comparative strength 

 and other properties of Iron, made with the hot and cold blast, at 

 the Carron, Devon, and Buffrey Works, under similar circum- 

 stances ; the former he considered somewhat weaker, and its specific 

 gravity somewhat less, except at the Devon Works. 



Section B. — Chemistry and Mineralogy. 



President — llev. Professor dimming. 



Vice-Presidents — Dr. Dalton, Dr. Henry. 



Secretaries — Dr. Apjohn, Dr. C. Henry, W. Herapath, Esq. 



Committee — Dr. Barker, Professor Daubeny, Rev. W. Vernon Harcourt, 

 Professor Hare, Professor Johnston, Professor Miller, Richard Phil- 

 lips, Esq., Drs. Roget, Turner, R. Thomson, T. Thompson, and Yel- 

 lowley ; W. West, C. Coathupe, G. .Lowe, H. Watson, Esqrs., Col. 

 Yorke, Rev. W. Whewell. 



Monday. — The first paper read was on the Phosphate of Soda, 

 and consisted merely of chemical details. 



Mr. Ettrick produced and explained an improved blow-pipe, and 

 Mr. Hare, of Philadelphia, a somewhat similar apparatus. 



Mr. W. Herapath gave an Analysis of the Bath Waters, and fur- 



