284 PROCEEDINGS OP THE AMERICAN ACADEMY 



Count Rumford, and from Dr. F. Garrigou, requesting the 

 Academy to send him samples of the principal American 

 thermal springs. This last was referred to the Smithsonian 

 Institution. 



Professor John Trowbridge, on behalf of Professor J. D. 

 Whitney, presented a paper on the velocity of the shock of 

 the Hell-Gate explosion. 



Mr. W. A. Rogers exhibited a series of drawings of the 

 planet Jupiter, by Mr. L. Trouvelot ; he also presented, by 

 title, a paper, by Mr. L. Waldo, on the pitch of the screw 

 of the micrometer of the equatorial of the Harvard College 

 observatory. 



Mr. S. P. Sharpies presented the following papers by title : — 



On the aceto-arsenite of copper. 



On some further determinations of standard milk. 



Six hundred and ninety-sixth Meeting. 



December 13, 1876. — Monthly Meeting. 



The President in the chair. 



The President read a letter from Mr. Alfred Tennyson, 

 accepting his election as Foreign Honorary Member ; also, a 

 letter from Mr. William Ferrel, resigning his fellowship. 



The following papers were presented : — 



O'n the structure of the chrysalis of butterflies, by Mr. 

 S. H. Scudder. 



On the two-point and three-point problem in surveying, by 

 Professor E. C. Pickering. 



On the water of the ponds of eastern Massachusetts, by 

 Mr. S. P. Sharpies. 



Six hundred and ninety-seventh Meeting. 



January 10, 1877. — Stated Meeting. 



The President in the chair. 



The following papers were presented : — 



On the micrometer level, by Professor E. C. Pickering. 



