OF ARTS AND SCIENCES : APRIL 10, 1866. 99 



make such arrangements with the Boston Athenaeum as they 

 may find feasible and deem expedient. 



On the motion of Mr. Paine it was voted that application be 

 made to the representatives of the late Jonathan P. Hall, for 

 the meteorological observations made by him during the past 

 nine years under the auspices of the Academy, and forming a 

 sequel to the observations of Mr. Hall already published by 

 the Academy. 



Mr. Paine was appointed to make this application, and also 

 to receive the apparatus furnished by the Academy for Mr. 

 Hall's use. 



Mr. C. M. Warren presented the following paper: — 



Note on an Improved Apparatus for the Determination of 

 Vapor Densities by Gay-Lussac^s Method; being a Mod- 

 ification of Bunsen's Apparatus for measuring Aqueous 

 Vapor. By 0. M. Warren. 



Having recently had occasion to employ the method of Gay-Lussac 

 for taking vapor densities, I decided to follow the lead of Carius,* and 

 substitute for this purpose the steam-bath apparatus, Fig. 1, devised by 

 Bunsen,t for measuring the aqueous vapor formed in the analysis of 

 gases, — this seeming to me preferable to the apparatus described by 

 Gay-Lussac. But when I came to use the apparatus which I had 

 constructed, in conformity, as I supposed, with that of Bunsen, I 

 found it defective in one particular. I allude to th& fact that, in con- 

 sequence of the accumulation of a stratum of water on the surface of 

 the mercury in the cup i, Fig. 1, in which the measuring-tube, e, stands 

 inverted, and also of an accumulation of water in dew-like drops on the 

 sides of this cup, and on the sides of the cylinder c c, it was found im- 

 possible to make an accurate reading of the lower level of mercury. J 



As I was about to abandon the use of this apparatus and resort to 

 that of Gay-Lussac, it occurred to me that the defect above mentioned 



* Annalen der Chemie und Pharmacie, CXIX. 316. 



t Gasometrische Methode, p. 52 ; English edition, p. 47. 



I It is but just to remark, that my apparatus may have been defective in its pro- 

 portions, — as dimensions were not given in Bunsen's description, — for it does not 

 appear that either Bunsen or Carius had any difficulty in making accurate observa- 

 tions with the apparatus that they employed. 



