Rubber, Resins, Paints And Varnishes

PREFACE. THE object the author of the following treatise has proposed to himself has been to put into as condensed a form as was consistent with the nature of the subject the knowledge and information dispersed through a numerous collection of authors who have treated thereupon. They are mostly in foreign languages for it is much to be regretted that our own scientific authorities have not thought it worth their while to occupy themselves with this highly important branch of practical chemistry. The author has endeavoured, as conscientiously as possible, to avoid any questionable theory, or to quote - as practical results any cases of whose correctness reasonable doubts might be entertained. There are, it is true, some theories propounded, some practices recommended, which are in direct contradiction to those usually received in England. They have not, however, been so advanced, unless the long experience of the most distinguished foreign engineers has warranted him in believing that our own practice is based entirely upoil prejudice. We are, whether far good or for evil, essentially a practical nation-we have a dislike to theory, almost to analysis-we examine reluctantly any habit we have long followed. As in politics, so we are even in building. Our forefathers made mortar in one way, as perfect as their knowledge admitted, and doubtlessly that way was all that was practically necessary to secure the results then sought for-so we continue without examination in the track they beat for us. Onr requirements are, however, very different. Railroads, and the constructions they necessitate, have modified very materially the science of construction. In England, especially of late years, works have been executed which so immeasurably surpass in boldness anything which had been previously attempted, that we may be justified in expressing our surprise that so few attempts have been made to ascertain the real nature of t, he materials dealt with. Is it not to this neglect that we may attribute the numerous failures we read of Some of these failures have been so remarkable, and some recent business transactions have displayed so singular an inattention to the nature and properties of lime, that the author deems it his right to provoke a discussion upon the subject, trusting that abler heads and hands will complete what he has so imperfectly begun. This branch of chemical knowledge has been so. entirely L revolutionised of late, so mucl1 nncertainty still remains to overshadow it, that it would be worse than folly to make any assertion which would lead to a belief that even the very fundamental principles were not, even now, susceptible of modification. That which is to be desired above all things is to rouse the professions of engineers and architects from the apathy with whic, h they treat such subject, as the one hefore us-the very alpha and omega of their business. There is, however, something SO invidious in attacking PREFACE. V openly n generally received opinion, as the author has done with respect to the mode of making mortar prac-. tised in this country, gage 66 and subsequently, that he throws himself upon the consideration of his professional brethren, the hope that they will excuse his boldness orr the score of his sincere desire to t dvtlncet he true interests of science. At the same time the author would beg to protest very energetically against therule-of-thumb methods which prevail in England in the manipulation of mortars...