MANUFACTURE OF SALT. 
117 
their high price would prevent their general introduction. All things taken into the account, 
if a precipitant is necessary or desirable, pure lime, used in the manner and with the precau¬ 
tions heretofore given, will probably be preferable to all others. 
To the question which is so frequently asked, How can the manufacture of the fine salt be 
improved ? I can answer only in general terms, by imitating as closely as possible the processes 
observed in the coarse salt fields. This should be the standard, for here salt is obtained in 
the purest form, and yet by operations entirely simple, and easily varied to suit particular 
cases. In applying these principles to the manufacture of fine salt, it cannot be too strongly 
urged, that the first purification of the brine, or the separation of the less insoluble impurities 
which subsequently form the pan scale, should be effected in vessels (whether reservoirs or 
pans) other than those in which the salting is to take place. A want of attention to this point 
is, in my opinion, one of the principal causes of the complaints which have been made in re¬ 
gard to this salt. Indeed, the condition of the kettles, containing, as they often do, a deposit 
of these impurities of three or four inches in thickness, on which the salt is deposited, and 
from which it is removed by simple ladling and drainage, forcibly exhibits the objections to 
which this mode of manufacture is ordinarily exposed. 
Another objection to the fine salt, as it is often manufactured at the Onondaga furnaces, is, 
that it is wet, and forms into solid masses which can with difficulty be removed from the bar¬ 
rels into which it has been packed. Its weight is thus almost fraudulently increased, and its 
value for various purposes seriously impaired. This arises from the want of care in removing 
the bitterns, a term applied to designate the highly deliquescent chlorides of calcium and 
magnesium. These substances, in consequence of their great solubility, remain with the salt; 
and the drainage to which it is subjected after being taken from the kettles, is intended to 
effect their removal. But oftentimes this drainage is not sufficiently long continued; and the 
result is, that these deliquescent substances are still in a great proportion mixed with the salt. 
The separation of these might perhaps be more advantageously and completely effected by 
putting the salt into a vat having a double bottom, and pouring on it small quantities of cold 
water. Performing this operation, if necessary,- two or three times, the bitterns or easily so¬ 
luble matters would be carried off, while the pure salt would remain; a very small portion 
only of which would be dissolved. I am satisfied that a strict attention to the two points 
above noticed, viz. the separation of the less soluble materials in vessels other than those in 
which the salting is effected, and the complete removal of the bitterns by drainage or washing, 
would entirely remove the objections which have heretofore, with too much truth, been urged 
against the Onondaga fine salt. 
I have only to add to the remarks which have already been offered, that several manufac¬ 
tures, in which common salt is employed, might be advantageously carried on in the vicinity 
of our brine springs. Among these are the soda ash, or British barilla, which is now so ex¬ 
tensively used in the manufacture of glass and soap ; the various preparations of soda for 
medicinal use ; and the chloride of lime, of which large quantities are consumed in the process 
of bleaching. The manufacture of sulphuric acid, or oil of vitriol, might perhaps be as well 
