202 



to taper down the displaced water to a fifth or tenth of one grain. It 

 is true, that Mr. Stevenson's apparatus is mainly designed for sub- 

 stances lighter than water ; but it is also intended for those that are 

 heavier ; and, in either case, so large a scope for the divisor would 

 produce very irregular and unreliable results, as it appears to us. 



The graduated tube was thought of, and experimented upon ; and, 

 after all, it was found that a balance would be indispensable, to obtain 

 satisfactory results. A very fine instrument is not generally requi- 

 site, and the weighing can be done nearly as soon as an observation 

 can be made of the marked degrees. 



As to the stopcock at the end of the spout, Mr. Stevenson must 

 soon find that this is a superfluity; and, more than that, a source of 

 error and vexation. We found this the case in a supposed improve- 

 ment, of French invention, in drawing off the dose for humid assays 

 of silver. A drop of water, or a bubble of air, will lie concealed, and 

 spoil the result, or render it uncertain. 



As the specific gravities of solids fighter than water, have hitherto 

 been obtained by a complex operation, and as the apparatus of Mr. 

 Eckfeldt is specially adapted to obtain such gravities by a direct and 

 simple mode, we propose, at a future day, to offer to the Society a ta- 

 ble of results, as found by this method; particularly of the different 

 kinds of wood, charcoal, &c. 



The Secretary was directed to inform the Royal Bavarian 

 Society of Sciences at Munich, that this Society is unable to 

 comply with their request to be supplied with duplicate copies 

 of the publications of the iVm. Philosophical Society. 



The Academy of Sciences at St. Louis, JNlissouri, and the 

 Elliott Society of Natural History, of Charleston, S. C. were 

 ordered to be placed on the list of Corresponding Societies. 



A letter signed J. R. Lambdin, dated Philadelj)hia, June 12, 

 1856, and addressed to the American Philosophical Society, 

 was read, in which Mr. Lambdin informs the Society that it 

 is his intention shortly to visit Europe, and that he desires, 

 while there, to execute original portraits of some of the most 

 eminent scientific men of the countries which he may visit: — 



Whereupon, a ])reamblc and resolution upon the subject were 

 offered by Mr. Henry D. Gilpin, which were read and post- 

 poned for consideration at the next meeting of the Society. 



