Telegraph Insulators, they should never be dark

TELEGRAPH INSULATORS.

It has generally been supposed that any kind of glass was good enough for telegraph insulators. The statement of an expert telegrapher, however, is that the glass used should as near approach flint as possible, and should never be dark. The reason given is that insects gather in the "bell" of the insulator in order to shelter themselves from the sun or weather; that dying in there, they become knitted and matted together, and absorb and retain sufficient moisture from the atmosphere to greatly interfere with the electric current. The experience of years of observation proves that insects gather sparingly, and in many cases not at all, under insulators made of bright, light transmitting glass.