458. Memoir on Sulphuric Ether. 
vity, .769, arid might therefore be considered 
as’ between the second and third quality. 
_ The modifications of the boiling point of 
ether produced by water, however, are the 
most astonishing. ‘The heavy fluid arising 
from the washing of ether by water, which 
is of the specific gravity .96, and which con- 
sists of 8 or 10. parts of water and J or 2 of 
ether and alcohol, boils at 103° in the tube ; 
but if the temperature be increased it soon 
ceases to manifest the increasing progressive 
elasticity of pure ether, as may well be ex- 
pected. Thereason 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. 
Specific Gravity of Ether Vapour. 
In 1803 and 1804 I made a great many 
experiments on the combustion of ‘ether va- 
pour mixed with oxygen gas by electricity. 
These sufficiently demonstrated the great 
