Visit to the Salt Works of Zipaquera. 91 
and information of eee among whom its principles are to be ap- 
plied. 
The impure salt taken from the rock is principally used to strength- 
en the water from the salt springs which rise in its neighborhood, 
and contain from ten to eighteen degrees of strength ; the point of 
saturation being twenty five degrees, regulated by an instrument 
graduated for that purpose. I was told that after various experi- 
ments it was found, that water at any degree of temperature would 
not take up more than one fourth of its weight of salt. 
The water from the salt springs is received into a large basin of 
substantial mason work coated with cement, built in the time of the 
Spaniards ; large lumps of the rock salt are cast in to saturate it, after 
which it is drawn off to be filtered into large earthen pots containing 
from seven to fifteen gallons, arranged in an arch of a very peculiar 
construction over a furnace heated by wood and bituminous coal, 
found in large quantities in the vicinity. From one hundred and sixty 
to one hundred and eighty earthen pots of a sugar loaf form, are ar- 
ranged in an arch over the furnace, (which is a large, square apartment, 
like an open shallow cellar,) in lines beginning at each side, being 
supported below by the faggots and coal, and at the sides by unburnt 
bricks plastered with clay, which fill up the interstices between the 
pots, leaving here and there, apertures for the smoke to escape; after 
the first four hours of the process these apertures are closed up. 
When the rows of pots approach the center, a row of the largest size 
are ranged in the middle like key-stones to an arch, and the whole 
fabric is supported by lateral pressure, after the wood and coal which 
at first serve as a resting point, have burnt away and consolidated 
the clay which is dashed i in between the sides of the pots. 
The saturated salt water is at first thrown into the exposed mouths 
of the pots in small quantities, as a glaze; they are then gradually 
filled up with grained salt, prepared in the ordinary manner in large 
iron pans. For twenty four hours after, salt water of the highest 
grade of saturation is thrown in occasionally, (the mouths of the 
range of pots being reached by calabashes fixed to long handles,) in 
order to consolidate the texture throughout the mass in the pots. 
Fresh wood is cast into the furnace underneath the arch for twenty 
four hours, and the pots are left in their position for forty eight hours 
afterwards, to receive the heat of the cinders, which are occasionally 
raked up. This continued heat of seventy two hours renders the 
salt of a marble-like firmness and appearance ; being glazed on the 
