Wooden Matches for Artillery . 53 
ide. If too little oxide be used, the salt will be acidu- 
lous, and soon destroy the boilers. To obtain the mean 
term, 500 parts of litharge should be put into a vessel of 
glass or earthen ware, and on this should be poured 41 § 
parts of nitric acid at 40°, (specific gravity, we belie ve,, 
1.386) diluted with 128 parts of water; heat the mix- 
ture till the oxide is dissolved, filter, and evaporate to 
dryness. These proportions ought to produce 640 parts 
of lead. 
Bath of Nitrate of Lead » 
The nitrate of lead is very soluble in water, and the 
least possible quantity of liquid should be employed, that 
the bath, fully loaded, may acquire a temperature far be- 
yond that of boiling water, and thus insinuate itself ea- 
sily into the pores of the dilated wood. Accordingly f 
for every pound of nitrate, only a wine quart of water 
should be put into the boiler, or thereabout : but as dif- 
ferent kinds of wood do not saturate themselves equally 
with the salt, their proportions must be studied. Expe- 
riment has shewn that to absorb a pound of nitrate of 
lead, requires near eleven yards of lime wood, 17 i of 
birch, and near 22 of poplar. The lime therefore, when 
saturated is the most combustible. 
To render the saturation of the wood complete, six 
hours boiling are necessary, and hot water must be add- 
ed, when the bath sinks so low as to let the salt fall to 
the bottom. 
Second Drying of the Matches . 
When the matches are taken out of the boiler, they 
must be carried to the stove, and made thoroughly dry* 
before they are put into the following bath. 
