VOL. v.] PHILOSOPHICAL TRANSACTIONS. 55^. 



but the 7 th about noon all trees of that kind bled very freely, both at the twigs 

 and body, and I struck above a dozen. 



At this critical season I was willing to repeat the experiment on other trees ; 

 and to this end I forthwith struck the hawthorn, hazel, wild rose, gooseberry 

 bush, apple tree, cherry tree, blather nut, apricot, cherry-laurel, vine, wal- 

 nut ; yet none bled but the last ; and that faintly in comparison of the syca- 

 more. This is consonant to our former experiments : and if it did happen that 

 these sycamores bled not all this winter before at the wounds made the first of 

 November, I now think, that if new wounds had been still made at every 

 break of frost, some signs, at least of our Yorkshire bleeding, might have been 

 discovered before novi^. 



In all the monuments of the ancients, collected by the great industry of 

 Pliny, I find but few instances of this nature. Amongst those few, one is re- 

 gistered with two or three remarkable circumstances to our purpose. He tells 

 us, that the physicians of old, when they had a mind to draw the juice of the 

 mulberry- tree, were wont to strike it skin deep only, and that about two hours 

 after sun-rise. This experiment is twice mentioned by him, and in both places 

 as a strange phenomenon. We might make our comment upon the places, 

 but for this time are content only to transcribe the texts. Lib. l6. c. 38. 

 Mirum ; hie (cortex) in Moro, Medicis succum quaerentibus, fere hord diei 

 secund^, lapide incussus manat, altius fractus siccus videtur. Lib. 23. c. 7. 

 Mora in ^gypto et Cypro sui generis, ut diximus, largo succo abundant, 

 summo cortice desquamato, altiore plag^ siccantur ; mirabili natura. 



Some Observations concerning the Variety of the Running of Sap in 

 Trees, compared with a Weather Glass; made in April, I67O. 

 With some Ways of ordering Birch Water. By Dr. Ez. Tonge. 

 N' 68, p. 2070. 



I am this day veiy much confirmed in my apprehension, that trees and other 

 plants, if we could contrive them, as I have projected in my Sap-wiser to that 

 purpose, would far better indicate the alteration of weather, as to heat, cold, 

 moisture, drought, than any weather glasses I have yet tried. For though 

 my weather glasses continued at the same station all this day, (April 13) my 

 trees have altered their temper so much, that 24 of them which ran tolerably 

 this forenoon, yield not a pint of sap this afternoon ; and though one of them 

 ran most part of the day, the rest ceased about one or two o'clock in a fair 

 clear sun-shiny season, retarded only by a western wind ; though that be re- 

 puted mild and cherishing. 



