PREFACE.

In the following pages I have endeavoured to give a concise but comprehensive account of the largest branch of chemical industry of this country.

Importance has been attached in this attempt, to matters of history, interesting as they are in showing how gradually knowledge is perfected. It will, for instance, be seen that at no time in the history of the Alkali Trade has an inventor brought into use a totally new process; so-called new processes are but the perfected forms of old ones, and are based upon previously known facts. Moreover, the greatest commercial successes have been achieved, not by the practical application of new ideas, but in the development of old ones. Taken as a whole, this trade wel exemplifies the truth that scientific investigations necessarily precede industry.

Men, from time to time, discover new facts, either by following out a process of mu of induction constructed upon a knowledge of the relations existing between previously known facts, or by accident. Accidental discoveries are somewhat inevitable in experimental science, where the method of enquiry depends upon reasoning, for the correctness of which there is no absolute test. But for