CHAP, iv SYLVA 93 



i oo weight edge- wise ; and a piece of \ inch thick, 

 \\ broad, 2 foot long, broken with 125 weight, also 

 edge-wise. 



The experiment was order'd to be repeated and 

 recommended by the President, to Sir Will. Petty 

 and Dr. Hook ; and it was suggested by some of the 

 company, that in these tryals consideration might be 

 had of the age, knottiness, solidity, several soils and 

 parts of trees, Gfc. and Sir Robert Morray did parti- 

 cularly add, that it might be observed how far any 

 kind of wood bends before it breaks. 



MARCH 64. 



The operator gave an account of more pieces of 

 wood broken by weight, viz. a piece of fir 4 foot 

 long 2 inches, 53 ounce weight, broken with 800 1. 

 weight, and very little bending, with 750 ; by which 

 the hypothesis seems to be confirm'd, that in similar 

 pieces, the proportion of the breaking-weight is 

 according to the basis of the wood broken : Secondly 

 of a piece of fir two foot long, one inch square, cut 

 away from the middle both ways to half an inch, 

 which supported 250 1. weight before it broke, which 

 is more by 50 1. than a piece of the same thickness 

 every way was formerly broken with ; the difference 

 was guessed to proceed from the more firmness of 

 this other piece. 



His Lordship the President, was desired to contri- 

 bute to the prosecution of this experiment, and parti- 

 cularly, to consider what line a beam must be cut 

 in, and how thick it ought to be at the extream, to 

 be equally strong : Which was brought in April 13, 

 but I find it not enter'd. 



