While researching information on threadless insulators, telegraph companies and their lines, I came across some information in two different books (both from 1853) describing a glass block insulator which had two halves to it. These are the only references I have found pertaining to this two piece glass block. Does anyone have one of these in their collection?

To a limited extent the insulator represented by fig. 37 has been employed. It consists of two rectangular pieces of glass; in each is a semi-cylindrical groove, in which is laid the wire. In the figure the white part represents the two pieces of glass, one laid above the other. They are fitted into a bracket and a small board is nailed to the bracket to servo as a roof. The whole is attached to the post or to a tree.

"The figure shows the methods of attaching them to glass caps, by supporting the wire from their side, or resting them in a groove on the top; those caps fit over wooden or iron pins, which are fastened on the top of horizontal crossbars, or driven into the aide of the post; two blocks of glass in the form of a parallelepiped, and dovetailed together in such a manner as to let a wire, without any other fastening, slide through a central opening, the g lass being surrounded and protected by wood; the most recent method consists of glass blocks, fitted in cast-iron caps, and supported on the peg by a heavy glass tube (3). The caps, of whatever form, are either upon crossbars, or supported by iron staples driven into the post."