'A DISCOURSE

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BOOK III.

* Of tliespe-cifick Gravityof timber inproportion towater, fee thetable in thePhilosophicalTransactions ,n. ]i5£>, and199 .

J u N E 29, 1664.

There were made several experiments more of breaking wood: 'First, a-piece of Fir, half an inch diameter, and three inches long, at which dis-tance the weight hung, broke in the plane of the grain horizontally, with•sixty-six pounds and-three-quarters, whereof fifteen pounds Troy; verti-cally, with two pounds more. Also Fir of one quarter of an inch dia-meter, and an inch and a half long, broke vertically with twenty pounds,and horizontally with nineteen pounds. Elm of half an inch diameter,and three inches long, broke horizontally with forty-seven pounds; ver-tically with twenty-three pounds. Elm a quarter of an inch diameter,and an inch and a half long, broke horizontally with twelve pounds;, ver-tically with twelve pounds, which is note-worthy.

J-u i. v G, 1664.

The experiment of breaking woods prosecuted: A piece of Oak of halfan inch diameter, and three inches long, at which distance the weightbung, broke horizontally with forty-eight pounds ^vertically, with fortypounds. Ash of half an inch diameter, and three inches .long, horizon-tally with seventy-seven pounds; vertically, with seventy-five pounds.Ash of half an inch diameter, and an inch and a half long, horizontally

with nineteen pounds; vertically, with ten pounds.-Thus far the

■Register.

In the mean-time I learn, that in the mines ofMendip, pieces of timber,

■ of but the thicknefs of a man’s arm, will support ten tun of earth; andthat fome of it has lain two hundred years, which is yet as firm as ever,■growing tough and black; and being exposed two or three days to theAvind and sun, scarce yields, to the ax.

Here might come in the Problems of Cardinal Cusanus, in lib. iv.IdiotEC dial. 4to, concerning the different velocity of the ascent of greatpieces of timber, before the fmaller, fubmerged in water, as also of theweight; as v. g. Why a piece of wood an hundred pounds weight, poisingmore in the air than two pounds of lead, the two pounds of lead shouldseem to weigh (he should say sink) more in the water*? Why fruits, be-ing cut off from the tree, weigh heavier than when they were growing ?With feveral the like paradoxes, haply more curious than useful, andtherefore we purposely omit them; but so may we not the recommendation