Читать книгу A Manual of Mending and Repairing; With Diagrams онлайн

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Though mending or restoring is a subject which in some form comes home to and concerns everybody, and which it is assuredly everybody’s interest to understand, this is, I believe, the first book in which its application to a great variety of wants has been made, and that in such a clearly co-ordinated manner, and according to such a simple principle, that whoever reads it can have no difficulty in mending any object, even though it be not described here. In all works of the kind which I have seen the recipes for repairing have been given simply according to their subjects, without any view to general principles of application, and a great proportion of these were in turn simply copied from old books of miscellaneous “receipts,” or newspapers in which every so-called new discovery is announced as infallible, or as if it had been tried and tested to perfection. That I have not recklessly accumulated in this fashion all kinds of recipes to fill my pages will appear very plainly to every chemist or technologist, who will perceive that, proceeding from a comprehensive table of generally recognised and long-tested bases of cements, I have given deductions and combinations scientifically agreeing with their laws and with experiment. The true object of giving a great number of recipes has not been solely or simply to supply the house-keeper or mechanic with instructions for certain repairs, but also to suggest to the technologist and inventor new ideas and applications. Thus, when we know that given proportions of zinc in powder, silicate of soda, and chalk form a strong cement, resembling zinc, it is as well to suggest that this may be varied by employing other metals and substances, such as bronze-powders and mineral oxides, to be always preceded by a little experiment. I venture to say that any intelligent person who masters this work can, on this hint, make for himself innumerable inventions; and I am sure that there is not the editor of a single technological journal who will not testify to the fact that every year a great many patents are taken out and fortunes made from recipes which are neither so scientifically combined nor practically useful as those which I here give. That there are fortunes still to be made is abundantly proved by the fact that there are very few people, comparatively speaking, who know where to get or how to make waterproof glue, or how to mend with it, neatly and durably, shoes, umbrellas, and many rents in garments; how to unite a broken strap; mend, by felting, torn hats; rehabilitate perfectly worm-eaten and torn-away paper; restore decayed broken wood; or mend, in fact, anything except with common glue or mucilage—both of which soon give way and crack or melt. So long as such general ignorance prevails, just so long there will be an opportunity for the inventor to make and sell cements, and for the repairer to find employment.