Poor Insulating Properties of the Otis Lightning Rod Insulator

THE LIGHTNING ROD QUESTION.

To THE EDITOR OF THE MANUFACTURER AND BUILDER:

In the March number of your journal, your correspondents, J. D. West & Co., ask: "Who said the air "needs lightning; we did not." They did not use the expression, "needs lightning", but they have employed language to that effect. In your impression for July, 1890, they said: "The electricity seeks an equilibrium in the air as well as in the water of the earth." It seems almost incredible that they have studied forty years without learning the simple fact that electricity seeks an equilibrium only where it is needed.

For the last year they have been trying to make the readers of the MANUFACTURER AND BUILDER believe that a lightning rod without a ground connection can protect a building by dispersing the lightning into the air. Now they say: "It has been claimed by hobby experimenters that buildings can be efficiently protected by numerous points placed upon their roofs in metallic connection with each other, and without any ground connection."

I have recently examined some of West & Co.s rods with Otis insulators and dispersing points, and find that these points are only about five inches from the building. But they say the dispersion is not enough to reach the building that is, to go a distance of five inches. It follows that the rods should be only ten inches apart in order to equalize the electric tension in the air, which they (November 1890), said was necessary to protect a building.

The fears of the chief electrician of the Western Union Company "many years ago" that the point on the Otis insulator would injuriously affect the working of the wires, were not well founded, as is clearly shown by the fact that they do work well (in fair weather) with two points on every insulator. But for telegraphic uses this so-called insulator patented August, 26, 1851 has two fatal defects which the merest tyro in electrical matters ought to observe on first sight. A line could not he securely fastened to it, and it contains not the slightest provision for keeping a portion of its surface dry in wet weather. The Western Union Company could not he hired to use such a worthless piece of glass, even it had no dispersing point.

A lightning rod might protect, if there were stamped on it Please Keep off the Building, or, at the bottom, This Way Out. But would protection prove that such devices were useful!

Whitesboro, N. F., June 4,1891. J. E. SMITH.