170 ON THE MANUFACTUKE OF PRUSSIATE OF POTASH. 
ART. XXXIX.— ON THE MANUFACTURE OF PRUSSIATE OF 
ii'r.'' ,. ^ o.v, POTASH. 
■ By Ambrose Smith. 
The process employed in this country for the manufac- 
ture of prussiate of potash from animal material, is not essen- 
tially different from the old German method as described 
in works on Chemistry. 
Instead of the cast iron, egg-shaped pot or bomb/' as 
Usually figured, what is called a "shell," is employed; 
having the shape of half an egg divided longitudinally ^ 
about 4 feet long, 30 inches greatest diameter at top, and 
10 or 12 inches deep in the centre ; the thickness of the iron 
about 2 inches at top, increasing gradually to about4 inches 
at the bottom. 
This shell is set solid in loam on a brick or stone founda- 
tion ; at one end is the fire-hole of the furnace, the flame 
from which enters through a flue of about 5 inches by 8, 
directly into the shell, between it and a roof of fire tile, and 
passes through another flue about 4 inches by 5 in this roof, 
at the other end of the shell into the chimney stack. The 
roof which covers the shell, is composed of four or five tiles, 
14 inches wide, and of various lengths to suit, which are 
laid across the shell resting on a course of fire brick built 
around its edge, and covered with several courses of brick 
and loam. Opposite the fire-hole, directly under the exit 
flue, is the door through which the material is introduced 
into the furnace, and the fused mass removed when 
finished. 
In some factories the iron shell is dispensed with, a bed 
of fire brick set on edge, and built very closely, so as to be 
impervious to the fused potash being substituted for it, form- 
