196 Mr. J. E. Myers on a new Volumenometer, 



only from that due to Paalzow in a detail of construction. 

 Messrs. Gee and Harden* suggest a method of determining 

 the volumes of bodies, depending on the graviinetrical esti- 

 mation of the carbon dioxide occupying a vessel of known 

 volume in which the body whose volume is required is placed. 

 However, since a cubic centimetre of carbon-dioxide gas 

 weighs only '0020 gramme, it is clear that the accuracy 

 attainable in determining small volumes by this method can- 

 not be very great. The volumenometer about to be described 

 has proved itself capable of determining the volumes of bodies 

 with as great expedition and much greater accuracy than any 

 of the instruments above noticed. 



Let A, B, C, D represent the volumes of the cavities of the 

 vessels A, B, C, D. A is in connexion with C, and B with D, 

 as indicated in the accompanying figure. Suppose mercury 

 stands at the same level in each of the tubes c and d, and let 



Fic.l. 



the same pressure applied simultaneously compress volume C 

 into A, and volume D into B. The condition that the mer- 



* British Association Report, Newcastle, 1889. 



