No doubt most of you will have noticed the satisfactory results obtained by Mr. Hack, of the Saltley Gas Works, Birmingham, and by Mr. McMinn, of Kensal Green, with the furnaces employed by them for gaseous firing without recuperation, whereby they are enabled to save fuel and carbonize more coal per mouthpiece than with the old system.

He has three retorts, 14 by 16 inches, and 8 feet long, in an oven carbonizing 2 cwt. of coal every four hours; the heats are higher and more regular; and the retorts easier kept clear of carbon.

The process of carbonizing the delicate fabrics, leaves, grasses, etc., is as follows:

Of course, the method employed to carbonize the materials is suspectible of variation, but the scientific principles involved are unchangeable, viz.: (1) Partial exclusion of air and substitution therefor of a carbon atmosphere.

The operation of carbonizing woolen rags for the purpose of obtaining pure wool, through the destruction of the vegetable substances contained in the raw material, maybe divided into two parts, viz., the immersion of the rags in acid, with subsequent washing and drying, and the carbonization properly so called.