The Smoke Problem

Abstract

IN the above remarks by Prof. J. B. Cohen on the review of “Smoke: a Study of Town Air,” which appeared in NATURE of April 11, the reviewer is first taken to task for denying that “coal-dust is a product of incomplete combustion, and also that tar and free carbon are formed in the destructive distillation of coal.” The passage in the review was: “Dust is not, as a rule, a product of incomplete combustion, nor is the tar and free carbon formed in the destructive distillation of coal.” The reviewer is still of opinion that coal-dust is not a product of incomplete combustion; by a strong chimney draught some coal-dust may be drawn up the flue, but it has certainly not been produced by combustion (unless Prof. Cohen looks upon the natural formation of coal as a process of incomplete combustion). Prof. Cohen elects to read the second part of the sentence as a denial that tar and coke are formed during gas manufacture, but it is doubtful if anyone else will do so; the reviewer's statement is that the tar and free carbon formed in the destructive distillation of coal are not products of incomplete combustion.