§4' . DifcJ-ipt'ioh of Vim Mcrum^s Apparafus 



ed for the compolition of water, and fecufed againft tke en^ 

 trance of air in the like manner. This balloon, reprefented 

 by A (Plate II.), has two cocks B C with conical itoppcrs^ 

 and united to the tubes by the fame means as thofc in the- 

 gazomet^r ab«ve mentioned*. Within the balloon- is ar 

 fmall crucible of platina, d, fufpended by two wires of the 

 fame metal from the plate of copper by which the balloon 

 is Iliut. The cock B ferves to coimeft the tube with an 

 air pump, and by thefe means to empty the balloon of at- 

 mofpheric air. By the cock C, the oxygen gas. Contained 

 in the gaiiometer G, is introduced ; but as this gaS ought to 

 be as dry as poflible before it is admitted into the balloon, I 

 have applied between it and the gazometer a glafs cylinder, 

 11, fdled with a fait which ftrongly attrafts the moifture of 

 the gas. The fait which I found moft effe6lual in this ex- 

 periment was that ufed and reconmiended by Sauflure for 

 drying atmofpheric airf. It is the alkali which remains- 

 after the decrepitation of a mixture of equal parts of nitre 

 and cmde tartar, and which has been kept at a red heat for- 

 an hour. 



The fait in the tube Hmuft not be pulverifcd, but divided 

 into fmall fragments, in order that the gas may penetrate 

 through it, and come in contact with a greater portion 

 of its furface. The tUbes i, w, h, by which the cylinder H 

 is connefted with the gazometer and tho» balloon, muft be- 

 pliable, becaufe it vi'ould be too diflicult to place the cylinder 

 ^ in fuch a pofition as to be united with the balloon and 

 gazometer by means of tubes not capable of being bent. I 

 employ pliable tubes of gum elaftic, the ends of w hich are 

 faftened to the copper pipes fcrewed into the cocks. 



Lavoifier kindled the phofphoms in the balloon by a burn- 



• For a drfcription of the gazometer, or apparetus for producrng wattr 

 by combining hydrogen with oxygen., here refcrrtd to, kiXhc Fbilojh^hical 

 M.igazhit, vol. ii. p. 85. 



-j- Sec Dc Saullurt's Ffdisfur f Jh-^rcmeirif, p. 25. 



ing 



