Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. This volume was written for the wireman and contractor, with a view to giving him, not only some practical hints on latest construction methods, but also to suggest to him means for increasing his income. Many special devices have been described, which may sug gest to the contractor, an extra which he may sell his customer.