and of which the early Circles, or ligneous Coats, are thin, is weaker than the other.

Our Author found alfo that the Strength of Timber is proportioned to its Weight; fo that a Piece of the fame Length and Size is fo much the stronger as it is heavier. This Remark points out the Method to be observed in comparing the Strength of Trees brought from different Countries and out of different Soils; which may be of great Service to Carpenters; for by this Rule, they have only to weigh a Piece, or even the Pattern of it only, to afcertain the Strength of the Timber they intend to make use of, and thus to avoid the double Inconveniency, either of wafting it without Neceffity, which often happens; or to be too fparing of it, which is

much oftener the Cafe.

It may perhaps be imagined that a Piece, which, according to Mr. Buffon's Experiments, is freely fettled on two Treftles, muft bear much less than a Piece fastened by the two Ends, and fixed in a Wall, as are the Beams and Joyfts of a Building; but, fays our Author, if we take Notice that a Piece, for Inftance, 24 Feet long, while it bends fix Inches in the middle, which is often more than is requifite to break it, is raised only half an Inch at each End, and sometimes three Lines only, because the Load often draws the End out of the Wall, VOL. III. PART I. much

I

much more than it makes it rise, it will eafily appear that his Experiments may be applied to the common Pofition of Beams in a Building; the Force, which breaks them in making them bend, being a hundred times more confiderable than that of the Line-plaifter and Mortar, which yields and falls eafily; and he affirms, after having taken particular Notice of it, that the Difference between the Strength of a Piece laid on two Treftles and free at the Ends, and a Piece fixed in a Wall built as they commonly are, is fo infignificant, that it is not worth minding. Tho' he owns at the fame time, that to faften a Timber-piece with Iron Braces, to lay it on, and load it with Free Stones in a good Wall, encreases its Strength confiderably; and that, if it were poffible, invincibly and immoveably to faften it at the two Ends, and thus fix it in an inflexible and perfectly hard matter, nothing but an almoft infinite Force could break it.

In Buildings Pieces of Timber are loaded in feveral Places along their whole Length, whereas in the Author's Experiments the Load bore upon one fingle Place only,viz. the Middle; this makes a confiderable Difference, of which Mr. Buffon intends to take Notice in another Memoir.

To

To compare the Effects of Time on the Refiftance of Timber, and to discover how much it lofes in its Strength, our Author chose four Pieces eighteen Feet long and feven Inches thick; he had two to be broke, which fupported each of them nine thoufand Pounds weight for one Hour; and the two others he loaded with fix thousand only, that is to fay, the two Thirds of what the others fupported, and left them so to observe the Confequence. One of them broke at the End of five Months and 26 Days, and the other at the End of fix Months and 17 Days. This Experiment being over, he ordered two other Pieces of the fame Dimenfions to be wrought; and had them loaded with one half only, that is to fay, 4500 pounds,and kept them fo loaded for above two Years; they did not break, but bended pretty much; so that in Buildings defigned to laft long, it is proper to give the Timber but one half, at the moft, of the Weight which might break it, tho' in urgent Cafes and in Conftructions which are not to laft, as when a Bridge is made for an Army to pass over it, or a Scaffold either to fuccour, or storm a Town, the Builder may venture to give the Timber the two Thirds of its Load.

Our Author took the following Method to find out how much a Knot leffens the Strength of Timber, He looks I 2 upon

upon Knots as a Kind of Pegs inherent to the Timber, and fays, that the Depth of a Knot may, in a great Meafure, be known, by the Number of the yearly Circles it has. Having examined fome Knots in a Piece of Timber, he ordered his Carpenter to make Holes in the Form of Cones, and of the fame Depth, in Timber Pieces which had no Knots; he filled thefe Holes with Pegs of the fame Figure; had those Pieces broke and judged that Way how much Knots leffen the Strength of Timber, which is beyond what is commonly imagined; a Knot or a Peg, which happens to be in the lower Part, and efpecially at one of the Edges, does fometimes leffen by a quarter Part the Strength of the Piece.

Tho' this Memoir of Mr. Buffon's be very particular; yet the Subject is not exhausted; he intends to present another Memoir to the Royal Academy; I fhall not fail to give an Account of it as foon as it comes over.

ARTICLE.

VIII.

La Sainte Bible, ou le Vieux & le Nouveau Teftament avec un Commentaire literal, &c

That is to fay,

The Holy Bible, or the Old and New Teftament, with a Literal Commentary made

up

up of chofen Notes out of feveral English Authors. Tom. I. Containing the first Book of Mofes, or Genefis. 4° Hague 1742, with Privilege from the States of Holland. Pag. 158 for the preliminary Difcourfe, the Preface on the Pentateuch and chiefly on Genefis, the Chronolo gical Table for this Book, and the Advertifement; and 416 pag. for the Body of the Work, besides a copious Table of Contents and five Geographical Maps. I. Of the Garden of Eden. II. Of the Settlements of Japheth. III. Of the Settlements of Shem. IV. Of the Settlements of Ham. V. Of the Land of Canaan and the neighbouring Countries at the Time of the Patriarchs. Tom. II. Ift Part containing the fecond Book of Mofes, or the Exodus. Hague 1743. Pag. 386, befides the Advertisement; Dr. Arbuthnot's Table of Meafures, Coins, and Weights, formerly in Ufe among the Jews; a preliminary Difcourfe on Exodus, and a Map of the Journey of the Ifraelites through the Defart.

MR

.

R. Chais an eminent Clergyman at the Hague is the Author of this Work, one of the most useful that came out these feveral Years paft. Tho' it be not fo advantageous to English Readers,

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on