Methylene. 
hydrogen C 4 H 4 , which forms the radical of all the combina- 
tions- of which we are about to speak. So, according to 
them, spirit of wood is a bihidrate of methylene, consisting of 
one volume of vapour of water, and one volume of methy- 
lene, condensed into one volume. 
Spirit of wood, exposed to the contact of air and black 
platinum is converted into formic acid, whilst common alco- 
hol, submitted to the same action gives acetic acid. The 
acids exert a special action upon spirit of wood ; it is, how- 
ever, worthy of remark, that the action of the oxygenated 
acids, such as nitric acid, is much weaker than that which 
the acids exert upon alcohol. 
When a solution of potash, in spirit of wood, is put in con- 
tact with sulphuret of carbon, it forms a product analogous 
to that which M. Zeise described under the name of hydro- 
xanthate de potasse. Spirit of wood dissolves the resins per- 
fectly, and as it is more volatile than alcohol, it is very con- 
venient for making varnish. 
HYDRATE OP METHYLENE. 
Thus the authors name the gas obtained in distilling a mix- 
ture of one part of spirit of wood and four parts of concen- 
trated sulphuric acid. This gas is to spirit of wood what 
common sulphuric ether is to alcohol ; that is to say that the 
bihydrate of methylene, (spirit of wood,) has lost half of its 
water to form ordinary ether. This gas presents indeed to 
the eudiometric analysis the following composition, C 4 H 4 H 3 0. 
Hydrate of methylene is a colourless gas, has an etherial 
odour, and burns with a pale flame. Water at 18° C. dis- 
solves thirty-seven times its volume. When the bihydrate of 
methylene is made to act on the hydracids, new compounds 
are obtained, perfectly analogous to hydrochloric, hydriodic, 
and other ethers of alcohol. In these compounds there 
always enters a volume of acid for a volume of methylene. 
HYDROCHLORATE OF METHYLENE. 
This is easily obtained by heating a mixture of two parts 
of sea-salt, one of spirit of wood, and three of concentrated 
