This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
The art of domestic bell-hanging is quite modern, and was but little in practice before the present century. At first it was usual to expose the wires to view along the walls and ceilings, even in the best houses, until the "secret system" was introduced, which consists in carrying the wires and cranks in tubes and boxes concealed by the finishings of the walls. The tubes are generally of tinned iron or zinc; but they ought to be either of brass or strong galvanized iron. Zinc cannot be depended upon: in some places it will moulder away; if not soldered, it opens, and the wires work into the joinings of the tube, which stops their movement. The proper time to commence bell-hanging is when the work is ready for lathing; but it should not be delayed till after the rough-cast plastering has commenced. If the work be performed at this period, it enables the bell-hanger to see his way more clearly, and prevents much cutting away of the plasterers' work afterwards.
The bells are usually hung in a row on a board placed in a convenient position for being seen and heard by the attendant; each bell having some mark by which to distinguish the room whence the summons proceeds. Each bell is connected by a separate wire with a handle fixed in the room to which it relates. The wire of communication, which transfers the jerk of the handle of the bell-pull to the bell, can only travel in straight lines following the walls of the rooms or passages traversed, consequently at each change of direction the continuity of the wire must be broken, and the ends attached to the arms of a suitable crank. These are made in several forms to suit the situations which occur, and must be chosen accordingly. It is important to have as few cranks as possible, because they all help to increase the wear on the wires, tubes, etc. In some houses no provision is made for bells. Where it. is desired to remedy this defect, a very long handled (2-3 ft.) gimlet, called a "belllianger's gimlet," Fig. 1377, is needed for boring passages for the wires, unless the additional expense is incurred of letting in tubes for the wires to run in. The wire used is of copper, Nos. 16, 17, or 18 gauge for indoor work, and 14 or 15 for outdoor.
The wire should be strained quite tight when put up, and secured at one end to the chain on the bell-pull, and at the other to the lower arm on the bell, allowing the latter to hang perpendicularly. The bell-pull, bell, and cranks must be very firmly secured in their places; joints in the wire are always made by looping and twisting, with the aid of a pair of pliers which also cut off the ends. The whole system is very crude as compared with the electric system, which is now coming into general use.