f 
ON THE MANUFACTURE OF PRUSSIATE OF POTASH. 177 
A patent for a process by which the nitrogen of the air 
is appUed under much more favourable circumstances, was 
taken out in England, in 1S43, by Mr. Newton, patent 
agent, on account of a foreigner, a detailed description of 
which, being an extract from the specification, has been re- 
pubhshed in this journal. This process consists in causing 
a steady current of air, to be drawn by means of a suction 
pump downward through a column of alkalized wood or 
other carbon, in fragments contained in a fire clay cylinder, 
maintained at a white heat. For a particular description 
of the apparatus, we refer to the 19th vol. of this Journal. 
Soon after this method was first published, we tried it on 
the experimental scale with promising results. The appa- 
ratus employed by us, suggested by that described in the 
specification, consisted of a wrought iron cylinder, open at 
the lop, and having a small screw orifice at the bottom, 
being a mercury bottle inverted, the bottom of which had 
been cut off. This was set upright in an open furnace, a 
curved gun barrel screwed into the smaller orifice passing 
between the bars of the grate out of the draught hole of the 
furnace. To the gun barrel a leaden tube was connected, 
which passed into a Wolfe's bottle containing water, for the 
purpose of washing and cooling the gases; this bottle was 
connected by another tube with a suction pump. 
The iron cylinder having been heated to bright redness, 
one and a half pounds of wood charcoal in small pieces, 
which had been impregnated with half a pound of pearlash 
by solution, and subsequent drying, was thrown in. As soon 
as the mixture became heated, the pump was put in action, 
drawing a current of air through the ignited alkalized 
charcoal, the gases resulting being washed in the Wolfe's 
bottle before reaching the pump. The operation was 
continued about three hours. The gas drawn through 
during most of the time was nearly all carbonic oxide, 
which, on the application of a lighted taper, ignited and 
burnt continuously with a light blue flame, at the exit pipe 
16^ 
