18a Account of the American Sugar Maple. 



fome frefli leaves, minced as has been directed, may be in- 

 fufed in a mixture of vitriolic acid and water, of about the 

 degree of acidity of vinegar ; and it may be neutralifed as it 

 is wanted, by chalk, or fixed or volatile alkali. Avoid an 

 excefs of alkali, as it will turn the colour yellow. 



By the fame procefs Mr. Watt made a red infufion of vio- 

 lets, which on being neutralifed formed a very fenfible teftj 

 but how long it might be preferved, he had not determined. 



Mr. Watt recommends to ufe the tefls in a liquid ftate; as 

 he obferves, and with juftice, that the fize and alum in writ- 

 ing-paper in fome degree fix the colour, while paper not 

 fized becomes too tranfparent, when wetted, to render 

 final} changes of colour perceptible. 



To the above ufeful hints of Mr. Watt we fhall add ano- 

 ther. — The (kins of red radimes yield by being bruifed a very 

 fenfible teft, and, no doubt, might be preferved by the means 

 he has pointed out. 



XIV. An Account of the Sugar Maple of the United States, 

 hy Benjamin Rush, M. D. Vrofeffor of the Injlitutes of 

 Medicine in the Univerjity oj Pennfylvania, communicated 

 hr Robert John Thornton, M. D. Leclurer on Me- 

 dical Botany at Guy's Hofpital. 



T 



JL HE acer faccharinuni jf Linnaeus, or fugar maple tree, 

 is found in great abundance in the weftern counties of all the 

 middle ftates of the American Union. Thofe which grow 

 in New York and Pennfylvania yield the fugar in a greater 

 quantity than thofe which grow on the water of the Ohio. 

 Thev are'when at maturity, that is, when about twenty years 

 old, as tall as an oak, and from two to three feet in dia- 

 meter. They put forth a beautiful white bloflbm in the 

 fpring before they Ihew a fingle leaf. The colour of the 

 blolTom difiinguillies the fugar maple from the acer rv+ 



brum, or common maple, which has a red flower. Its fmall 



branches 



