304 Manufacture of Pot and Pearl Ashes. 
pointed out above; viz. by roasting, treating hie nitric 
acid, and subsequent fusion with borax. 
With great respect and esteem, 
your ob’t serv’t, 
JAMES F. DANA. 
Pror. SILiiman. 
Ant. XXVI.—Notice of the method of manufacturing the 
Alkaline Salts of Commerce. a Dr. Gustavus A. 
RocErs.* 
Tuese salts are known in market by the names of Pot 
and Pearl Ashes. The difference between the two salts 
depends on a difference in the process of manufacturing. — 
The pearl ashes generally bear a price in New-York of 
from five to fifteen dollars more per ton than the pot ash. 
To obtain the pot ash, so called, it is necessary to put 
into the leechesin which the ashes are acted on by water, 
a quantity of quick lime. This is placed at the bottqm of 
the tub. Where lime is plenty, from an half bushel to a 
bushel is put in each tub. Without this precaution, the 
“black salts,” asthe boilers term them, are very difficult 
to fase. Indeed it is almost impossible to do it with any 
common fire, except such salts as are made in the spring, _ 
when the frost and snow are leaving the ground. The ley 
obtained is evaporated by a large fire, and the process is hur- 
ried as fast as possible. After two or three days, they 
cease to refill the kettles, and evaporate the mass to the 
consistence of West-India sugar. Ifitbe intended to make the 
pearl ashes, the mass is removed from the kettles; but if the 
pot ashes are intended, itis not removed; but as great a heat 
is raised as the mere combustion of the best wood will pro- 
duce, in the large arches over which the kettles are placed. 
The process requires from two hours to one half or three quar- 
ters of a day, as the salts are for purity. During the fusion, 
the impurities that are combustible are destroyed, exhibit- 
ing sparks of fire, and some gaseous matter continues to es~ 
cape, which agitates the more fluid part. When it is com- 
nletely in a state of fusion, it is perfectly at rest, and exhib- 
* Furnished by request of the Editor. 
