BULLETIN OF THE BUSSEY INSTITUTION. 439 
axs 
lxg 
(a) D= 
in which 
a = the observed angle; 
1 = the length of tube; 
g = the number of grm. of dextrose in s, as determined by Fehling’s liquor; 
s = the number of c.c. of the saccharine solution taken. 
I have designated these approximate rotations as ‘* quasi- 
(a) D,” and it is to be observed that the results set forth in 
this article have all been obtained in this way, unless otherwise 
expressly stated. 
It should be observed that although the figures of the quasi- 
rotations are always somewhat higher than those of the true 
specific rotations, they must nevertheless depend upon definite 
relations which subsist between the quantities of sugar detected 
in the solutions and the angles of rotation actualy observed in 
the polariscope. 
For the sake of illustration a sample of pure dextrose was 
tested in the manner and by the formula above stated, and there 
was obtained as the approximate specific rotation of this sub- 
stance, quasi(a) D = 56°.84; while pure galactose (from Merck 
& Co.) treated in the same way gave quasi(a) D = 86°. 
Whereas, the true specific rotations (a) D = 53°.40 (for dex- 
trose) and (a) D = 79°.94 (galactose) were obtained on testing 
these very samples in the conventional way and calculating from 
the observed data by means of the proper formula, viz. 
a(p+q) x 1.00125 , 
ani Sa in which 
a = the observed angle; 
p =the number of grm. of sugar; 
gq = the number of grm. of water; 
1 = length of the tube; 
d= sp. gr. of the solution at 17°.5; 
1.00125 = factor for reducing the sp. gr. to 4°C. 
In the preliminary trials above mentioned, it appeared as a rule 
that the rotatory power exhibited by the products of hydrolysis 
was appreciably higher than could have been the case if only 
dextrose had been present. Thus, several specimens of maple 
wood, hydrolyzed as above described, after the action of strong 
acid and tested in the manner indicated gave the results which 
here follow: quasi(a) D = 63°, 65°, 66°, 68°, 69° and 73°.5, re- 
