company had a considerable sum arising annually to be laid out in books, and needed a judicious friend in London to transact the business for them, he voluntarily and cheerfully undertook that service, and executed it for more than thirty years successively, assisting in the choice of books, and taking the whole care of collecting and shipping them, without ever charging or accepting any consideration for his trouble. The success of this library (greatly owing to his kind countenance and good advice) encouraged the erecting others in different places on the same plan; and it is supposed there are now upwards of thirty subsisting in the several colonies, which have con tributed greatly to the spreading of useful knowledge in that part of the world; the books he recommended being all of that kind, and the catalogue of this first library being much respected and followed by those libraries that succeeded.

During the same time he transmitted to the directors of the library the earliest accounts of every new European improvement in agriculture and the arts, and every philosophical discovery; among which, in 1745, he sent over an account of the new German experiments in electricity, together with a glass tube, and some directions for using it, so as to repeat those experiments. This was the first notice I had of that curious subject, which I afterwards prosecuted with some diligence, being encouraged by the friendly reception he gave to the letters I wrote to him upon it. Please to accept this small testimony of mine to his memory, for which I shall ever have the utmost respect; and believe me, with sincere esteem, dear Sir, B. FRANKLIN.

Your most humble servant,

TO MICHAEL HILLEGRAS, Esq. PHILADELPHIA. On covering Houses with Copper. :

DEAR SIR,

London, March 17, 1770.

I received your favor of November 25, and have made inquiries, as you desired, concerning the copper covering of houses. It has been used here in a few instances only, and the practice does not seem to gain ground. The copper is about the thickness of a common playing card, and though a dearer metal than lead, I am told that as less weight serves, on account of its being so much thinner, and as slighter wood-work in the roof is sufficient to support it, the roof is not dearer, on the whole, than one covered with lead. It is said that hail and rain make a disagreeable drumming noise on copper; but this, I suppose, is rather fancy; for the plates being fastened to the rafters, must, in a great measure, deaden such sound. The first cost, whatever it is, will be all, as a copper covering must last for ages; and when the house decays, the plates will still have intrinsic worth. In Russia, I am informed, many houses are covered with plates of iron tinned, (such as our tin pots and other wares are made of,) laid on over the edges of one another, like tiles; and which, it is said, last very long; the tin preserving the iron from much decay by rusting. In France and the Low Countries I have seen many spouts or pipes for conveying the water down from the roofs of houses, made of the same kind of tin plates, soldered together; and they seem to stand very well.

With sincere regard, I am, yours, &c.

B. FRANKLIN.

TO SAMUEL RHOADS, ESQ.

Containing the Method of covering Houses with Copper.

DEAR FRIEND,

London, June 26, 1770.

It is a long time since I had the pleasure of hearing from you directly. Mrs. Franklin has, indeed, now and then acquainted me of your welfare, which I am always glad to hear of. It is, I fear, partly, if not altogether, my fault that our correspondence has not been regularly continued. One thing I am sure of, that it has been from no want of regard on either side, but rather from too much business, and avocations of various kinds, and my having little of importance to communicate.

One of our good citizens, Mr. Hillegras, anxious for the future safety of our town, wrote to me some time since, desiring I would enquire concerning the covering of houses here with copper. I sent him the best information I could then obtain, but have since received the inclosed from an ingenious friend, who is what they call

"The carpentry of the roof being formed with its proper descents, is, in the first place, sheeted or covered with deals, nailed horizontally upon the rafters, after the same manner as when intended to be covered with lead. The sheets of the copper for this covering are two feet by four, and for covering the slopes of the roof are cast so thin as to weigh eight or nine pounds, and for covering the flats or gutters, ten or eleven pounds each, or about one pound, or a pound and a quarter to the superficial foot.

"A string of strong cartridge paper (over-lapping a little at its joints) is regularly tacked down upon the sheeting of wood, under the copper covering, as the work proceeds from eaves to ridge. It prevents the jingling sound of hail or rain falling upon the roof, and answers another purpose, to be mentioned by and by.

here a civil engineer. I should be glad you would peruse it, think of the matter a little, and give me your sentiments of it. When you have done with the paper, please

"In order to shew the regular process of laying down the roof, we must begin with fastening two sheets together lengthwise. The edges of two sheets are laid down so as to lap or cover each other an inch, and a slip of the same copper, about three and a half inches broad, called the reeve, is introduced between them. Four oblong holes or slits, are then cut or punched through the whole, and they are fastened or riveted together by copper nails, with small round shanks and flat heads. Indents are then cut 1 inch deep upon the seam at top and bottom. The right-hand sheet and the reeve are then folded back to the left. The reeve is then folded to the right, and the sheets being laid on the roof in their place, it is nailed down to the sheeting with flat-headed short copper nails. The right-hand sheet is then folded over the reeve to the right, and the whole beat down flat upon the cartridge paper covering the sheeting, and thus they are fastened and laid in their places, by nailing down the reeve only; and by reason of the oblong holes through them and the reeve, have a little liberty to expand or contract with the heat and cold, without raising themselves up from the sheeting, or tearing themselves or the fastening to pieces. Two other sheets are then fixed together, according to the first and second operations above, and their seam, with the reeve, introduced under the upper ends of the seam of the former, so as to cover down about two inches upon the upper ends of the former sheets; and so far the cartridge paper is allowed to cover the two first sheets. This edge of the paper is dipt in oil, or in turpentine, so far before its application, and thus a body between the sheets is formed impenetrable to wet; and the reeve belonging to the two last sheets is nailed down to the sheeting as before, and the left-hand sheet is turned down to the right. Four sheets are now laid down, with the seam or joint rising to the ridge; and thus the work is continued, both vertically and horizontally, till the roof be covered, the sides

to give it to Mr. Hillegras. I am told by Lord Le Despencer, who has covered a long piazza, or gallery, with copper, that the expence is charged in this account too high, for his cost but one shilling and tenpence per foot, all charges included. I suppose his copper must have been thinner. And, indeed, it is so strong a metal, that I think it may well be used very thin.

It appears to me of great importance to build our dwelling-houses, if we can, in a manner more secure from danger by fire. We scarcely ever hear of fire in Paris. When I was there, I took particular notice of the construction of their houses, and I did not see how one of them could well be burnt. The roofs are slate or tile, the walls are stone, the rooms generally lined with stucco or plaster, instead of wainscot, the floors of stucco, or of six-sided tiles painted brown, or of flag stone, or of marble; if any floors were of wood, they were of oak wood, which is not so inflammable as pine. Carpets prevent the coldness of stone or brick floors offending the feet in winter, and the noise of treading on such floors, overhead, is less inconvenient than on boards. The stairs too, at Paris, are either stone or brick, with only a wooden edge or corner for the step; so that, on the whole, though the Parisians commonly burn wood in

and ends of each sheet being alternately each way, undermost and uppermost.

"The price for copper, nails, and workmanship, runs at about eight pounds ten shillings per cwt. or two shillings and threepence per foot superficial, exclusive of the lappings; and about two shillings and eightpence per foot upon the whole; which is rather above half as much more as the price of doing it well with lead."