57 B PHILOSOPHICAL TRANSACTIONS. [anNO I67I. 



left all night in the grass-plot, and returned the next day to the fire-side, bleed 

 afresh. — Maple and willow-poles bleed and cease at pleasure again and again, if 

 quickly withdrawn and balanced in the hand, and often inverted to hinder the 

 falling and expence of sap : Yet being often heated, they will at length quite 

 cease, though no sap was at any time sensibly lost. And when they have given 

 over bleeding, that is, showing any moisture, by being brought within the 

 warmth of the fire, the bark will yet be found very full of juice. — A hard liga- 

 ture made within a quarter of an inch of the end of a wood-bine rod, did not 

 hinder its bleeding at all when brought within the warmth of the fire. — Maple 

 and willow-poles, &c. quite bared of bark, and brought to the fire, will show no 

 moisture at all in any part. — One barbery, or pipridge-pole, bared of its bark, 

 brought to the fire, showed moisture from within the more inward circles, 

 though not any from the outward. Maple and willow poles, &c. half bared of 

 bark, would bleed by the fire, from the half only of those circles which lay 

 under the bark. — Maple and willow-poles, split in two and planed, would not 

 show any moisture on the planed sides, but at the ends only. — A pole of ivy 

 did of itself exude and show a liquid and yellowish rosin from the bark and near 

 the pith ; but when brought to the fire-side, it bled a thin and colourless sap 

 from the intermediate wood circles. — A pole of willow (for example) bent into 

 a bow, will ooze its sap freely, as in bleeding either spontaneously or by the 

 fire. 



Extract of a Letter from Francis IVilloughby, Esq., March 16, 

 I67O-I, relating to some Particulars above-mentioned in M. Lister's 

 Communications. N° 70, p. 2125. 



We have reviewed our old notes, and made some few experiments, and find 

 that branches of willow, birch, and sycamore, cut off and held perpendicularly, 

 will bleed without tipping; and that the cutting off of their tops does not 

 sensibly promote the bleeding. We doubt not of Mr. Lister's diligence and 

 veracity, but wonder that our experiments should diff'er.* The trials we have 

 made this year confirm those we communicated to you formerly, viz. The 

 sycamore bleeds upon the first considerable frost, after the leaf is fallen, as it 

 did plentifully the 1 6th of November last : And both that walnut and maple 

 bleed all winter long after frosts, when the weather relaxes, and the acm shines 

 out ; but walnut and maple begin not so soon as the sycamore. The birch will 

 not bleed till towards the spring. This year it began something ^sooner than 

 ordinary about the beginning of February. / 



* See this difference removed below, by Mr. Lister himself. 



