3d. Philosphical and Literary Intelligence; under which head will be included, as far as practicable, whatever is interesting to the Physician, Naturalist, Agriculturalist, and Philosopher. Accounts of Literary and Humane Associations; Proceedings of learned Societies; Reports of Public Hospitals; Notices of new Publications, &c. and by means of an extensive correspondence, the editors trust they will be able to present the earliest intelligence of the discoveries in science abroad.

New-York, June 1, 1810.

CONDITIONS OF PUBLICATION.

The work will appear regularly every three months. It will be printed on a good paper, with a new and beautiful type; occasionally enriched with engravings.

Each number will contain about 100 pages octavo, forming an annual volume of 400 pages. The price to subscribers will be two dollars per

annum.

The first number was published on the first day of July, 1810, by EZRA SARGEANT, corner of Wall-street and Broadway, New-York; by whom subscriptions are received.

Communications are respectfully solicited, addressed to the "Editors of the American Medical and Philosophical Register," and transmitted to the Publisher, New-York.

THE

AMERICAN

MEDICAL AND PHILOSOPHICAL

REGISTER.

JULY, 1810.

ORIGINAL COMMUNICATIONS.

I.

REMARKS upon the incorrect manner in which IRON RODS are sometimes set up for defending houses from LIGhtNING. Communicated to the Editors, by HUGH WILLIAMSON, M. D. L. L. D. &c. &c.

As sundry buildings have lately been injured by light. ning, though they were provided with conductors or iron rods, it has been questioned by some of our fellowcitizens whether such rods can be deemed a sure defence against the violent explosions of the electric fluid.

A house on this island, about seven miles from the City-Hall, was struck with lightning, and considerably injured, although is was armed with an iron rod.

Trinity Church in this city is armed with a large iron rod, but the lightning, some years ago, forsook the rod,

7

four or five feet above the ground, and shattered the top of a wooden fence that inclosed the church yard.

A house in Savannah, the property of Mr. B. Maurice, was struck with lightning, and some furniture in the parlour considerably injured, although that house was provided with a rod. Two or three other instances have occurred to the southward, not unlike the cases mentioned, of houses being affected by lightning that were provided with rods. It is not worth while to detail the particulars, for in each case the lightning rod was unjustly blamed. The injury arose from the inattention or mistake of those who erected the rods, or who should have kept them in order.

By showing the error in two or three cases, the reader will be enabled to account for every accident of the kind.

It is known that iron is an excellent conductor of the electric fluid. Water is also a very good conductor. There are other bodies through which it will pass, but with considerable difficulty, as dry clay, dry wood, and stone. But it will not, by any means, pass through glass, bees wax, &c. Hence it follows, that an iron rod will conduct a flash of lightning from a cloud to the moist earth, along a wall of wood, brick or stone, without affecting the wall. But if the lower extremity of the rod terminate in dry sand, the electric fluid will only be partially conducted by the rod. And if the lower extremity of the rod should chance to terminate upon a large cake of wax or plate of glass, the whole flash of lightning would forsake the rod and enter the house, through which it could pass, though with difficulty, shattering the wood, &c.