PREPARATION OF CHARCOAL BY STEAM. 283 
places where small fissures in the boiler permitted the escape 
of steam, which, thus liberated, could not have a tempera- 
ture exceeding 212°. Where no leaks existed, the felt in 
contact with the boiler remained unaltered. Another case 
was that presented by the wooden float-guage of a brewing- 
copper, which had been exposed during five years to the 
vapor and the saccharine solution, at a temperature of 215° 
or 216° Fahr. The apparently carbonized wood was found 
permeated by a soluble salt of copper, and the interstices 
were filled with octohedral and dodecahedral crystals of 
metallic copper, the effect of slow reduction by the organic 
matter. These cases, however, appear totally distinctfrom 
ordinary carbonization effected at a temperature approach- 
ing or exceeding the boiling-point of mercury, inasmuch as 
they required a very lengthened period of time. They 
more resemble the effects of those great operations of Nature 
in which coal and other bituminous substances have been 
produced by the action of water upon vegetable and other 
organic matter buried deep in the earth by the changes 
which take place upon its surface, and probably not ex- 
posed to a higher temperature than the depth at which they 
lie of necessity involves. The blackened and disintegrated 
wood and felt were probably in a condition more resem- 
bling humus than charcoal, and might have been found on 
examination soluble to a great extent in solution of pot- 
ash. — Pharm. Journ. 
