Brooks Patent Insulators, not liable to be damaged by lightning

Brooks' Patent Insulators not Liable to be

Damaged by Lightning.

BROOKS' PATENT INSULATOR WORKS,

No. 22 South Twenty-first street,

PHILADELPHIA, Sept. 29.

TO THE EDITOR OF THE TELEGRAPHER.

YOUR issue of the 19th instant contains the following in the letter of your Chicago correspondent:

"Previous to the great fire here all the wires of the Western Union Company in this city were strung on "Brooks Insulators," and I am informed by one in authority, who ought to know whereof he affirms, that the wires have never tested so satisfactorily since, from the fact that on repairs recently in the city, the "Brooks" have not been used, for what reason I am unable to state. The Kenosha insulators have been used recently on repairs here in the city. An intelligent line repairer of my acquaintance, who has given insulation a good deal of thought, says the Brooks is the best insulator made, that although the first cost is much more than any other insulator its insulating properties are so vastly superior to any other he has used in his fifteen, years' experience in line building and repairing that they are by far the cheapest insulator in the market. He makes one serious objection to them however, which Mr. Brooks might, remedy. The objection is that the way they are now constructed lightning bursts up through them, destroying their insulating properties of course, and it passes through the insulator in such a manner that the defect cannot be noticed by a repairer unless he climbs each pole and examines each insulator. Not being an insulation man I do not suggest a remedy, but give, the information for what it is worth. Several of the Burlington and Quincy and some of the Michigan Central Railroad wires are strung exclusively on Brooks' screw shank insulators. And give great satisfaction, working well in either wet or dry weather."

Your correspondent stays, "The way they (the Brooks' insulators) are constructed the lightning bursts up through them, destroying their insulating properties, of course." Now I beg leave to say to your Chicago correspondent that lightning, does nothing of the kind. Lightning does not injure them in any manner. There are ten thousand insulators of mine used outside of Chicago to one used in Chicago, and that complaint has come from Chicago alone. If one of these insulators is heated on a stove to a point above 240 degrees Fahrenheit, the outer iron case will burst, provided the insulator is set upon the hot stove bottom upwards, in a manner that the sulphur nearest the stove and at the top of the insulators, is first melted. Many of the Brooks insulators that have Leon subjected to the flames of the Chicago conflagrations have been bursted from this cause-but lightning has had nothing to do with it--a pot or vessel of sulphur, when allowed cool, and then melted or heated at the bottom first will burst the vessel on account of the expansion which takes place in the change, from a solid to a liquid state.

The fewer the number of wires upon a set of poles the greater are the disruptive effects of lightning. I have never seen a pole or insulators injured where there were as many as thirty wires. There were from thirty to sixty wires upon the poles in Chicago. The greater the number of wires the more is the charge divided and dissipated. I refer to ordinary insulators, but with the Brooks Insulators a pole with but one wire is very seldom injured; as the number of wires are increased the disruptive effects of atmospheric discharges are proportionately decreased.

DAVID BROOKS.