One method consists in pulverizing animal charcoal until reduced to an impalpable powder. This is mixed with a definite proportion of Norway tar and a compound of other combustible substances. The combined materials are then properly amalgamated with liquid pitch, and the whole kneaded up into a homogeneous plastic mass which admits of being moulded into slabs or blocks of any required dimensions and shape. These blocks, having been allowed to dry and harden, are subsequently carbonized by being subjected to a process of incineration by heat; and in this manner all the combustible ingredients are burned out, leaving nothing behind but the animal charcoal in the form of a block of charcoal, permeated throughout by innumerable pores.