402 
Bock IV. 
Action of 
alkakies. 
M acide 
Of oilk 
Of heat. 
VEGETABLE SUBSTANCES. 
ed ; for it disappears almost completely by exposing the 
wax, drawn out into thin ribands, for some time to the 
atmosphere. By this process, which is called bleach 
ing, the yellow colour of the wax disappears, and it 
becomes very white. Bleached wax is not affected by 
the air *. 
Wax is insoluble in water and in alcohol. It com 
bines readily with alkalies, and forms with them a soap 
which is soluble in water, and possesses the properties 
of common soap. Punic wax, which the ancients em 
ployed in painting in encausto, is a soap composed of 
twenty parts of wax and one of soda†. Its composition 
was ascertained by Mr Lorgnat. 
The acids have but little action on wax; even oxy 
muriatic acid, which acts so violently on most bodies, 
produces no other change on it than that of rendering 
it white. This property which wax possesses, of re 
sisting the action of acids, renders it very useful as a 
lute to confine acids properly in vessels, or to prevent 
them from injuring a common cork. 
Wax combines readily with oils, and forms with 
them a substance of greater or less consistency accord 
ing to the quantity of oil. This composition, which is 
known by the name of cerate, is much employed by 
surgeons. 
When heat is applied to wax it becomes soft ; and 
at the temperature of 142°, if unbleached, or of 155° 
if bleached §, it melts into a colourless transparent 
fluid, which concretes again, and resumes its former 
* Senebier, Ann. de Gim, xii. 60. and Jour. de Pbys. XXXviIi. 56. 
1 Jour. de Phys. Nov. 1785. 
Pliny, lib. xxi. c.14. 
Nicholson's Joeraul, i-71.