P. E. Carpenter's P/, on the "Valorous." 437 



bottle is lowered and released from its cage, — the whole pro- 

 cess being the work of a few seconds. At the first filling, there 

 sometimes remains a small amount of air in the siphon, so that 

 the solution becomes slightly turbid on standing ; but this 

 effect of oxidation can be easily avoided by using a sufficient 

 amount of marble powder in charging the generator. This 

 siphon unquestionably affords the most convenient mode of 

 OSing hydric sulphide; and for a private laboratory a single 

 siphon, well charged, will afford as ample a supply as will 

 ordinarily be needed. It is greatly to be hoped that our 

 manufacturing chemists may soon find an advantage in sup- 

 plying this important reagent in such an elegant form* 



When the water is charged as directed above, it of course 

 holds in solution, besides hydric sulphide, a considerable vol- 

 ume of carbonic dioxide ; and if, under any circumstances, the 

 presence of this last gas would | - effect, the 



marble powder can be simply omitted in charging the gener- 

 ator. In almost all cases, however, the carbonic dioxide exerts 

 a very beneficial influence, and in several ways. In the first 

 place, it insures the non-action of the hydric sulphide on the 

 metallic surfaces of the apparatus. In the second place, it pro- 

 tects the solution from the action of the air when it is drawn 

 into an open vessel, so that after a metallic sulphide has been 

 precipitated by an excess of the reagent, the products may be 

 digested in an open flask or beaker without fear of oxidation. 

 In the third place, the carbonic dioxide adds greatly to the 

 tension of the confined gas, and enables us # to develop sufficient 

 pressure to charge the siphon without unnecessarily increasing 

 the strength of the solution of hydric sulphide. 

 Chemical Laboratory of Harvard College, 1876. 



Art. XLVIII. — Report on the Physical Investigations carried on 

 by P. Herbert Carpenter, B.A., in ILM.S. - Vahn 

 her Return Voyage /. ,i />-■• A '»■''' 1 '■/"*(, 1875; by 

 William B. Carpenter, C.B., M.D, F.B.S.f 



In the first of the Serial Soundings taken by the "Valorous," 

 nearly in the middle of Davis Strait and on the \- 



. the bottom-temperature, at a depth of 410 fathoms, 

 was 34-6° Fahr. ; and the descent to this from a surface- 

 temperature of 40° was nearly uniform— 39°, 38°, 37°, 36° and 



' All the apparatus here described may be obtained from the firm of John 



t Proc. Roy. Soc, vol. xiv, No. 113, p 

 Am. Joub. Sci.— Third Sbbies, Vol. 3 



