Insulators for Lightning Rods

INSULATORS FOR LIGHTNING RODS.

To THE EDITORS OF THE MANUFACTURER AND BUILDER:

Glass Ring Insulator. - The old Franklin rods often failed, because the lightning would leave the rod and follow the staples, which were kept clean and bright in the walls, and so penetrate and damage the building. To prevent this, the glass ring insulator was adopted, and came into general use. The idea was to insulate the rod from the staple. Experience proved their insufficiency. The rings were "so easily broken," as Prof. Henry declared, "that they were not of much use." Then professors and others concluded that insulation was a failure, and they rail against the glass ring to this day - condemning all insulation.

Fig. 1. - the Ordinary Glass Ring Insulator

More practical minds sought for a better kind, and Geo. W. Otis invented the insulator known by his name, which places a solid glass cylinder between the rod and the building, holding the rod in the shank of an insulated, pointed bracket, clasped on the outer end of the glass cylinder, so that the rod is not in contact with the glass, and there is no conductor from the rod to the building whatever, even though the glass should be broken. The other end of the cylinder is attached to the building by a movable iron collar, which makes a firm fastening not easily broken. The insulator thus furnishes a point to receive and disperse on the rod every five feet, as they are commonly used.

The Otis Insulator

This insulator satisfied Prof. Henry, who wrote that it was "the best thing he ever saw in Europe or America" for the purpose, and was highly commended by Profs. Horace Mann, R. O. Doremus, and others. We have used it for many years, and all over many others have used it the land, and we have challenged, and now again challenge, all who oppose insulation to point to a single instance where damage has resulted to any building upon which our rods have been properly placed, with the Otis insulator.

J. D. WEST & Co.,

40 Cortlandt street, New York.