WAX AND TALLOW. 
appearance as the temperature diminishes. If the heat 
be still farther increased, the wax boils and evaporates ; 
and if a red heat be applied to the vapour, it takes fire 
and burns with a bright flame. It is this property 
which renders wax so useful for making candles. 
Mr Lavoisier, by means of the apparatus which he 
employed in the analysis of alcohol and oils, and which 
has been described in the First Part of this Work, con 
trived to burn wax in oxygen gas. The quantity of 
wax consumed was 21.9 grains. The oxygen gas em 
ployed in consuming that quantity amounted to 66.55 
grains. Consequently the substances consumed amount 
ed to 88.45 grains. After the combustion, there were 
found in the glass vessel 62.58 grains of carbonic acid, 
and a quantity of water, which was supposed to amount 
to 25.87 grains. These were the only products. 
Now 62. 58 grains of carbonic acid gas contain 
44.56 of oxygen and 18.02 of carbon; and 25.87 gr. of water contain 
21.99 of oxygen and 3.88 of hydrogen 
21.90 
6655 
Consequently 21.9 parts of wax are composed of 18.02 
of carbon and 3.88 of hydrogen. And 100 parts of 
wax are composed of 82.28 carbon 
17.72 hydrogen 
ooa 
But this analysis can only be considered as an ap 
proximation to the truth ; the quantity of water being 
only estimated, and that of the gas being liable to un 
certainty. There can be no doubt, from the little ac 
tion of acids on wax, that it contains oxygen as an in 
* Lavoisier, Jour. de Pbys, XxXi. 59. 
204 
Chap. I. 
Its compo 
sition.