258 Botany. 
ever, be most entitled to confidence. Dr. Bigelow, in his 
paper on this subject, an abstract of which was given in the 
ist No. of this Journal, selected the Peach-tree, from the 
numerous plants whose time of flowering had been obser- 
ved. This was a very judicious selection. It seems de- 
sirable to prosecute the subject, and that several trees 
should be observed at each place, and at the same stage of 
flowering. ‘The last particular appears very important. For 
from the conclusion of Dr. Bigelow, it will be seen, that a 
difference of about four days, corresponds to a difference of 
one degree of latitude. Observers may be expected to 
differ at least two days in the tme that a tree may be thought 
to be fully in bloom. 
I have made these obvious remarks, because’ they pre- 
sent some of the difficulties in obtaining very definite and 
conclusive results upon climate from the > flowering of plants, 
unless there be very accurate and continued observations ; 
and, I have made them in this place, because they were con- 
nected with the immediate object. Whether these difficul- 
ties be considered as great as they appear to me, the con- 
clusion to be drawn from the observations upon the last four 
years in relation to a late or an early autumn, will not be es- 
sentially affected. 
Williams College, April, 1820. 
FOR THE AMERICAN JOURNAL OF SCIENCE. 
Art. X. On the manufacture of Sugar from the River Ma- 
ple, (Acer ertocarpum, of Lanneus 3) by Dr. Joux 
Locke. 
Ir seems not to be generally known, that sugar is afford- 
ed in any considerable quenity, by any other species than 
the sugar maple, (2cer saceharinum ;) but T have found that 
in some parts of New-England, more sugar is made from 
the river, than from the sugar maple. 
The facts I have ascertained, with regard to the ma- 
king of sugar from the river maple, I collected in Fryeburg, 
(Me.) on the Saco river, where large quantities are annually 
made; but before I state them, I will give some account of 
the two species, the sugar and river maple. F 
