VOL. XVII,] .PHILOSOPHICAL TRANSACTIONS. 423 



moon, between the 15th and 23d day of her age, says Vegetius; or rather, ac- 

 cording to CoUumella, between the 20th and the new moon. In general, says 

 Theophrastus, the oak must be felled very late in the winter, not till December, 

 as the emperor Constantinus Pogonatus positively asserts, the moon too being 

 then under the earth, as it is for the most part in the day-time in the first part 

 of its decrease. And the felling of oak. within those limits, they call tempestiva 

 caesura, felling timber in season, which they all unanimously pronounce, if thus 

 felled, it will neither shrink, warp, nor cleave, nor decay in many years ; it 

 being tough as horn, and the whole tree in a manner, as Theophrastus asserts, 

 as hard and firm as the heart ; with whom also agrees Mr. Evelyn. If you fell 

 not oak, says he, till the sap is in rest, as it is commonly about November and 

 December, after the frost has well nipped them, the very saplings thus cut, will 

 continue without decay, as long as the heart of the tree. 



And the reason of this is briefly given by Vitruvius, because the winter air 

 closes the pores, and so consequently consolidates the trees ; by which means, 

 the oak, as he and Pliny both express it, will acquire a sort of eternity in its 

 duration ; and much more so, if it be barked in the spring, and left standing 

 all the summer, exposed to the sun and wind, as is usual in Staffordshire and 

 the adjacent counties ; by which they find, by long experience, the trunks of 

 the trees so dried and hardened, that the sappy part in a manner, becomes as 

 firm and durable as the heart itself. 



And though this way of barking and felling of timber were unknown to the 

 ancients, as perhaps it is to all the world except those few counties, yet they 

 seem not unacquainted with the reason of the practice : for Seneca observes, 

 that the timber most exposed to the cold winds, is most strong and solid, and 

 that therefore Chiron made Achilles's spear of a mountain tree. Homer also 

 tells us, that the spear of Agamemnon was made of a tree so exposed ; for 

 which Didymus gives for reason, that being continually weather-beaten, it be- 

 comes harder and tougher. And Pliny says expressly as much for the sun, as 

 they for the wind, viz. That the wood of trees exposed to the sun-shine is 

 the most firm and durable ; for which reason also it is, that Vitruvius prefers 

 the timber on the south-side the Apennine, (where it winds about and in- 

 closes Tuscany and Campania, and strongly refiects the constant heats of the 

 sun upon it, as it were from a concave,) incomparably before that which grows 

 on the north side of the same hill, in the shady moist grounds : and his reason 

 is, that the sun not only exhales the superfluous moisture of the earth, whence 

 the trees are supplied in such shady places with too great a quantity, but in 

 great measure the remaining juices out of the trees themselves, rendering the 

 timber of them the more close, substantial, and durable; which certainly it 



