CHAP, iv Y L V A 95 



at which distance the weight hung, broke horizontally 

 with 48 L, vertically with 40 L ; ash of inch diameter, 

 and 3 inch long, horizontally with 77 L, vertically, 

 with 75 L; ash of inch diameter, and i^inch long, 

 horizontally with 19 L vertically, with 12 L &c. 

 Thus far the Register. 



In the mean time I learn, that in the mines of 

 Mendip, pieces of timber, of but the thickness of a 

 man's arm, will support ten tun of earth ; and that 

 some of it has lain 200 years, which is yet as firm as 

 ever, growing tough and black, and being expos'd 

 two or three days to the wind and sun, scarce yields 

 to the ax. 



1 8. Here might come in the problems of Cardinal 

 Cusanus in lib. 4. Idiotae diaL^*^ concerning the differ- 

 ent velocity of the ascent of great pieces of timber, 

 before the smaller, submerged in water ; as also of the 

 weight ; as e.g. Why a piece of wood 100 L weight, 

 poising more in the air than 2 L of lead, the 2 L of 

 lead should seem to weigh (he should say sink) more 

 in l the water ? Why fruits being cut off from the 

 tree, weigh heavier, than when they were growing ? 

 with several the like paradoxes, haply more curious 

 than useful, and therefore we purposely omit them ; 

 but so may we not the recommendation of that useful 

 treatise of duplicate proportion, together with a new 

 hypothesis of elastique or springy bodies, to shew the 

 strengths of timbers, and other homogeneous materials 

 apply'd to buildings, machines, &c. as it is published by 

 that admirable genius, the learned Sir William Petty. 

 To which we join that part of Dr. Crew's comparative 

 Anatomy of trunks , as variously fitted for mechanical 



1 Of the specific gravity of timber in proportion to w^ter, sec UC table in PfeZos. 

 Transact n. 169, and 199. 



