PREFACE.
The preparation of this hand-book was suggested by persistent questioning about the matters it contains. Its purpose is to furnish householders with information which has been so scattered, or buried so deep in technical discussions, that it has not been easy for them to find it for themselves. It is, of course, mainly a compilation, and the only difficulties met with have been those incident to the arrangement and condensation of a large mass of material. I have intended to give credit, where credit seemed to be due, for everything borrowed, and, if I have failed to do so in any case, it is not my fault, but my misfortune.
R. S. T.