1820.] Mr. Ballon on Sulphuric Ether. 123 



water, however, are the most astonishing. The heavy fluid aris- 

 ing from the washing of ether by water, which is of the specific 

 fravity 0-96, and which consists of 8 or 10 parts of water and 

 or 2 of ether and alcohol, boils at 103° in the tube ; but if the 

 temperature be increased, it soon ceases to manifest the increas- 

 ing progressive elasticity of pure ether, as may well be expected. 

 The reason of this is pretty obvious ; water possesses little or no 

 affinity for ether ; it yields readily the few atoms it possesses to 

 the influence of heat, and when they are raised, the supply 

 ceases. Hence we see the necessity of using a pure ether when 

 the tension at various successive temperatures is to be found. 



Sjiecijic Gravity of Fjher Vapour. 



In 1803 and 1804 I made a great many experiments on the 

 combustion of ether vapour mixed with oxygen gas by electricity. 

 These sufficiently demonstrated the great specihc gravity of this 

 vapour, as it was sufficient to have four or five per cent, of 

 volume of it to produce abundance of carbonic acid, and to 

 require a greater abundance of oxygen. I found it expedient to 

 ascertain as near as possible the exact specific gravity, and 

 attempted it as follows in September, 18U3. 



I took a balloon glass, of the capacity of 253 cubic inches, 

 having a wide neck, to which was adapted a brass cap and stop- 

 cock. Into this a graduated tube, -fV^s of an inch diameter, 

 containing ether of 0*758 specific gravity, and a manometer 

 were introduced ; the manometer was as usual a tube of -pyth 

 inch bore, closed at one end and duly graduated, with a globule 

 of mercury sliding in it. The vessel was immediately made air 

 tight, and kept so for several days, during which time the pro- 

 gress of the evaporation and of the gauge was occasionally 

 noted. The temperature of the air in the room was usually 

 about 55° ; but as this was of no importance, it was not particu- 

 larly noted. The observations follow : the ether tube was gradu- 

 ated into water grain measures ; barometer 30 inches. 



Sept. 23 2 p.m. 

 5 



8 



24 1 



9 



a. m. 



3 p.m 825 24-6 



10 818 28-5 



25 1 p. m 800 34-0 



12 795 38-9 



26 2 p.m 790 42-0- 



9 780 46-5 



28 9 a.m 772 49-5 



