201 



A communication by Dr. Leidy was offered, entitled " No- 

 tice of Remains of the Walrus discovered in the United 

 States/^ which was referred to Dr. Hallowell, Prof. Frazer and 

 Major Le Conte. 



A paper was presented and read from Messrs. Eckfeldt and 

 Dubois, explanatory of their communication read at the last 

 meeting, on an apparatus for determining specific gravities. 



Messrs. Eckfeldt and Dubois desire to offer a word of explanation, 

 in regard to the apparatus for taking specific gravities, which was 

 exhibited at the last meeting of the Society. A few days after that 

 meeting. Dr. Bache had the kindness to call upon us with a copy of 

 the May number of the London Pharmaceutical Journal, which he had 

 then just received. In it was detailed a contrivance, for the same 

 purpose, and on the same principles, which had been exhibited at the 

 North British Branch of the Pharmaceutical Society, held at Edin- 

 burgh on the 11th April. And it was further mentioned, that the 

 same apparatus had been shown at a meeting of the Royal Scottish 

 Society of Arts; and a committee, the chairman of which was Dr. 

 George Wilson, Professor of Technology, was appointed to report 

 upon its merits; which report was made on the 23d July, 1855, and 

 the Society's medal was awarded to Mr. P. Stevenson, the inventor. 



We have first to say, that, being entirely ignorant of these pro- 

 ceedings, and of this apparatus, we, of course, derived no aid or sug- 

 gestion from this source. It has so happened, as it has happened be- 

 fore, that the same idea was acted upon by two minds, independently, 

 and distant from each other, at nearly the same time. The experi- 

 ments of Mr. Eckfeldt began in December last. 



In regard to the principle, of operating by displacement, there will 

 be no dispute as to originaHty. It was the neat, convenient and accu- 

 rate application of this principle that remained a desideratum. 



The apparatus of Mr. Stevenson consists of a tall cylindrical ves- 

 sel, from which the displaced water runs off by a short spout near 

 the top, having a stopcock or faucet at the end. From this the water 

 runs into a graduated glass vessel of 3^ inches diameter. The object 

 of this graduation is to dispense with a balance, and save the trouble 

 of weighing. 



But any one who will take a vessel of only half that diameter, will 

 find that as much as fifteen grains of water may be added, or with- 

 drawn, and the eye will scarcely be able to see any difference. In the 

 apparatus of Mr. Eckfeldt, it was found desirable, for high gravities, 



