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. The primary Object Of the articles was to describe in detail the trunk system; but it was considered desirable to give some account of first principles, and accordingly the transmission of speech, transmitters, receivers, and, in fact, telephone stations generally, were briefly described. The writer is aware that much of this has been described times without number, but his experience as a teacher leads him to believe that the inclusion of this matter will render the book useful to a larger circle of readers. The first eight chapters may be said to be introductory to the subject of telephony generally. The permanent current systems nextly receive attention, and their various classes of switch sections. After this follow special switches, such as transfer boards, record table switch sections, etc.

The primary Object Of the articles was to describe in detail the trunk system; but it was considered desirable to give some account of first principles, and accordingly the transmission of speech, transmitters, receivers, and, in fact, telephone stations generally, were briefly described. The writer is aware that much of this has been described times without number, but his experience as a teacher leads him to believe that the inclusion of this matter will render the book useful to a larger circle of readers. The first eight chapters may be said to be introductory to the subject of telephony generally. The permanent current systems nextly receive attention, and their various classes of switch sections. After this follow special switches, such as transfer boards, record table switch sections, etc.