Coal Tar And Ammonia

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1887 edition. Excerpt: ...I give them in what appears to me to be the order of their importance: --"1st. A physical action. A very greatly increased solidity is effected by choking up the pores, thus agglutinating the whole. mass of the wood into a more or less solid block. Apart from its rendering the wood more solid, this physical action is important in preventing the subsequent absorption of moisture. "2nd. A physiological action. The smell of the creosote imparted to the wood prevents germinal life, well known to be destructive to timber, from being developed within it. Seeing that the preservation of timber has been effected by such materials as chloride of zinc, sulphate of copper, &c., with greater or less success, and that the action of these bodies must be mainly, although I admit not entirely, dependent on their toxic properties, this physiological action is one of importance. It must be remembered, moreover, that creosote has the advantage of a well-marked smell, which odour most of the lower animals dislike. In this respect it is superior to the other bodies I have named. "Further, it is worth pointing out that all the constituents of the coal-tar, and not the tar-acids only, have a more or less wellmarked tarry odour. "3rd. A chemical action. Respecting the chemical action, I would draw attention to the fact that tar-acids are not only antiseptic, but that they possess the power of coagulating albumen. It is to this latter action that I shall have to refer later on in this Report, as playing an important part, in my opinion, in the preservation of the timber. "Now, the two following questions arise: --(1 st) Upon what constituents of the creosote does its value specially depend, and what are the relative values of its...