LECT. HI.] THE SAP. Ill 



yet, been attempted on sap. As he does not, how- 

 ever, mention the state of the trees, from which the 

 sap for his experiments was taken, the result of the 

 analyses affords some reason for believing, that the 

 sap was not in the purest state. He examined the 

 sap of the Elm, Ulmus campestris, collected to- 

 wards the end of April, the beginning of May, and 

 the end of May. The result of the first analysis 

 was, that 1039 parts of this sap consisted of 

 1027-904 of water and volatile matter, 9-240 of 

 acetate of potash, 1-060 of vegetable matter, and 

 0-796 carbonate of lime. The second analysis of the 

 sap collected at the beginning of May afforded a 

 greater proportion of vegetable matter, less acetate 

 of potash, and also less carbonate of lime : and 

 in the third analysis of that collected at the end 

 of May, the quantity of the acetate of potash was 

 still more diminished, and also that of the carbonate 

 of lime *. In all he found slight traces of sulphate 

 and of muriate of potash. From two different ana- 

 lyses of the sap of the Beech, Fagus sylvatica, 

 procured also at different periods of the same 

 season, he obtained water, acetate of lime, free 

 acetic acid, gallic acid, and tannin, with some 

 vegetable extractive and mucous matter -}-. In the 

 same manner he examined the sap of the Common 

 Hornbeam, Carpinus sylvestris, collected in March 

 and April, and found in it, acetate of potash, 



* Annales de Chimie, t. xxxi. p. 21. 

 f Ibid, p. 26. 



