124 Jigorey on Heat and Laght. 
water, while evaporating, is whiter and freer from smoke. 
Ifa tunnel be inverted over the coal, the vapor as it issues 
from it may be inflamed. At first, in consequence undoubt- 
edly of the great proportion of water given off by the tar 
and coal, it burns without smoke. When the flame becomes 
reddish, and there is much smoke, pour a little water into 
the tunnel as it stands; it is received on the coal without 
driving out or exploding the tar, as it otherwise would. The 
vapor may again be inflamed, and again burns without smoke. 
Much in this way, may be had a useful he¢ht and fire for 
cooking especially at sea, and for a great aa other pur- 
poses. Ifthe tunnel be flatted, er rf the coal has been par- 
tially saturated with water, it burns with less smoke, and 
sand or ashes will prevent a loss by the side. Another 
great advantage derived from the coal, besides that of giving 
a more uniform steady fire, and preventing the tar’s running 
over, 1s the great quantity of water it absorbs, and that of 
the water’s adhering so obstinately to it, which in a great 
measure, answers every purpose of a constant supply of 
steam from a separate boiler. Newly made and red hot 
charcoal will take up about three times its weight of water, 
which it will in some measure retam until nearly consumed. 
Sand, ashes, or fine clay answers well for mixing with the 
tar &c. If the latter be made into a paste with equal parts 
of spirits of turpentine and water, and cold lumps of it of a 
conical form be placed on a table, and a flame applied, the 
vapors burn without smoke for a short time; if placed ona 
stove ata temperature something like that of boilmg water, 
the flame continues much longer. If enclosed in a tin cylin- 
der, and the vapor be made to issue through small holes at 
the top, placed as before stated, or on a plate over a chafing- 
dish of coals, it burns with a very white light, free from 
smoke. Ifthe cylinder be tight at the top, and the vapor 
be led froin the inside at the top, down and through the 
bottom and there be made to issue in an oblique direction, 
and from a number of small openings, it will burn with a 
beautiful fame, and supports and regulates, very accurately, 
its own evaporation. ‘The oblique direction carries the heat 
in part beyond the cylinder, when the evaporation is too 
reat. 
Every effect may be produced in consuming the smoke, 
and giving an intense white flame, by using a certain pro- 
