277 
1906-7.] Optical Rotation of Two Salts. 
277°‘42, it follows that the percentage probable error of the measurement 
in this case is equal to -■ ^. X i^? = 0 - 0148 per cent. 
27 1 '42 
The rotation results are as follows (see also figs. 2 and 3) : — 
A 
Solution (0). 
E. 
Solution (|). 
E. 
Solution (|). 
E. 
666 
25°-05 
69-6 
114'9 
598*5 
30-35 
85-6 
143-4 
550-5 
36-15 
104-0 
173-0 
515 
41-15 
121-3 
203-5 
487 
46-50 
138-1 
235-6 
455 
51-40 
166-7 - 
289-0 
A 
Solution (|). 
E. 
Solution (|). 
E 
Solution (1). 
E. 
666 
151° 1 
310°"4 
1404° 
598-5 
186-2 
392-7 
1482 
550-5 
228-0 
481-0 
1575 
515 
269-1 
571-0 
1668 
487 
314-3 
672-0 
1772 
455 
370-0 
769-0 
c. 1944 
Temperatures. 
(0) c. 
(4) 
c. 
(i) 
c. 
Q) c. 
(l) 
i c. 
(1) 
c. 
Concentration. 
B. 
A. 
B. 
A. 
B. 
A. 
B. 
A. 
B. 
A. 
B. 
A. 
I. 
24° 8 
2 5° 4 
25 °1 
25° 1 
25°0 
25° 1 
25°0 
2 5° 7 
25°2 
25° 6 
25° 1 
25°6 
O. 
24-3 
24-8 
24-6 
24-6 
24-2 
24-4 
24-4 
25-1 
244 
25-0 
24-6 
24-8 
Where “ A ” is the temperature of the solution after the rotation 
measurements. 
“ B ” is the temperature of the solution before the rotation 
measurements. 
“ I ” is the temperature of the solution at the end of the tube 
at which the heating water entered. 
u O ” is the temperature of the solution at the end of the tube 
at which the heating water left. 
Note . — The measurements were always made in regular order through the spectrum 
from red to violet. 
