In 1830, the fabrication of matches was not yet, properly speaking, a special industry. It was limited to a few poor families, who not having the means to purchase in any quantity the materials necessary to the fabrication, were forced to sell, from day to day, the product of their labor in order to be able to purchase new material.

The want of a machine which would eco-nomically manufacture wooden matches presented an insurmountable barrier to the development of that industry.

The work was done by hand, with imperfect tools, which very often wounded those who used them. After the invention of the first machine to cut matches, a single man could manufacture daily from 1800 to 2000 matches.

Chemical improvements favored also the development of this industry; oxygenated tinder-boxes largely increased; and, at last, the invention of inflammable mastic produced a complete revolution.

This new fabrication, of German origin, was established in other countries after a certain time.

In 1836 few factories were in operation, but since that time these establishments have greatly multiplied. Notwithstanding this rapid progress, the hygienic character of the business has not been much improved. While it may be considered as an industry most inju- rious to health, yet hygienists have not given us much light on the subject. The accidents which their fabrication, cartage, use, etc., are liable to produce in so great numbers have not yet been the object of scientific investigation.

The question of gun cotton is probably one of the most interesting which has risen into notice in the midst of the scientific movement of these last thirty-five years. The doubt has increased concerning the real value of this product and its applications. It is, therefore, useful to collect carefully all the elements of the question, to arrange them me-thodically, and to judge them with calmness and impartiality. It is with these views that this work has been composed.

First, we have shown the present state of knowledge concerning the composition and nature of its pyroxylic products, its ballistic properties, its applications in pyrotechny, surgery, photography, mining, etc.; its preparation, and the accidents which are liable to take place daring this preparation; the accidents no less serious which result from the handling of gun cotton, and its application to fire-arms.

Lastly, we have shown the causes of these accidents, the means to prevent them, and the processes of distinguishing gun cotton from ordinary cotton, not only in common use, but also in cases where it will be necessary to proceed to a judiciary inquest.

To the fabrication of matches and gun cotton, we have added researches upon a subject well worth the attention of hygienists.

Every one knows what development has taken place in the fabrication of fulminating powder, since percussion guns have been invented and used for war purposes; but, what is not so much known, is that this fabrication is of all industries, not only the most unhealthy, but the most dangerous.

To state those dangers, and in a few words indicate the means which science offers in order to prevent them, is one of the objects of the last section of this work.

New Lebanon, June 25,1864.