450 Proceedings of Philosophical Societies. [June, 



Article IX. 



Proceedings of Philosophical Societies, 



ROYAL SOCIETY. 



April 27. — A letter from Benjamin Bevan, Esq. to Dr. T. 

 Young, For. Sec. RS., was read, describing some Experiments 

 on the Elasticity of Ice. 



In this communication, Mr. Bevan first refers to some ex- 

 periments on this subject, made by him in the year 1824, 

 m which the modulus of elasticity of ice appeared to be above 

 6,000,000 feet, with the view of comparing their results with 

 those he obtained last winter from experiments on a larger 

 scale. In the latter, a prism of ice 100 inches long, 10 inches 

 wide, and of the mean thickness of 3*97 inches, being tried 

 with weights up to 25 pounds, exhibited a deflection of-^^^g^ 

 of an inch, which gives for the modulus 2,100,000 feet : and 

 on examining the calculations from his former results, the 

 author detected an error in the reduction, by the correction of 

 which he found them to indicate the same modulus as his more 

 recent experiments. In these, ice of various thickness, from one 

 and a half inch to four inches, and whether tried on the water, 

 or taken out and tried in the same way as wood or metal, gave 

 by computation the same modulus, as in the instance just 

 related. 



Mr. Bevan states that Dr. Young, in his valuable lectures, 

 has given 700,000 feet for the modulus of elasticity- of water, 

 computed from Canton's experiments on the compression of 

 that fluid ; but taking Canton's results under another point 

 of view, Mr. Bevan finds the modulus they indicate to be 

 2,178,000 feet ; which very nearly agrees with the result of his 

 own experiments on the elasticity of ice. 



In a note to this paper. Dr. Young states his opinion that 

 the same modulus should be yielded by sohds and by fluids ; 

 and he also refers to an experiment of his own, made some 

 years ago, on the sound given by a piece of ice, in which the 

 modulus did not appear to be greater than 800,000 feet. 



A paper was also read, on the application of the Floating 

 Collimator to the Dublin Circle ; by John Brinkley, DD., FRS. : 

 communicated by the Board of Longitude. 



Dr. Brinkley details, in this paper, the results of an examina- 

 tion to which he has subjected Capt. Kater's Floating Colli- 

 mator : they are favourable in the highest degree to the utility 

 of the instrument, which belongs. Dr. B. says, rather to a future 

 age of practical astronomy, than to the present. He finds the 



