Pamphlet by David Brooks on Lightning Rods

Facts and Inferences Relating to Lightning and Lightning Rods.

By DAVID BROOKS. Philadelphia

Franklin Institute. 1872.

The author of this pamphlet is well known as one of the leading electricians in America, and an occasional contributor to the columns of THE TELEGRAPHER. The little book before us is a reprint of a paper read before the Meteorological section of the Franklin Institute. Mr. BROOKS is the first person, as far as we are aware, to investigate the principles which govern the action of atmospheric electricity upon lightning rods, in accordance with the well settled laws of electrical accumulation and conduction, which have themselves but recently come to be well understood and appreciated. We have no space to follow Mr. BROOKS in his demonstrations, which are eminently clear and forcible, and, to the mind of an electrician, perfectly convincing.

Some of the conclusions he has arrived at may, however, be briefly stated. The universal defect of all the lightning rods in existence, with scarcely an exception, is in their defective electrical connection with the earth. Mr. BROOKS shows that as the conductive power of water, compared to iron, is as one to one thousand million, it is necessary that the ground plate should expose a surface as large as that covered by the building itself to insure adequate protection. In cities and large towns this is easily accomplished by attaching the conductors to the gas and water pipes. Unless at least a hundred square feet of metallic surface can be laid in a spring or body of water Mr. BROOKS considers that a building is safer without a rod. He disposes of the prevalent fallacy that the utility of a lightning rod depends upon the conducting surface of the rod itself, and that it must be insulated from the building.

The pamphlet is an exceedingly able one, and will well repay perusal. It may be obtained by remitting 25 cents to the Librarian of the Franklin Institute, Philadelphia, Penn.