504 PROFESSOK HENRY A. MIERS: AN ENQUIRY INTO 
Table VIIT. represents a series of observations made upon a solution of known 
strength gradually dduted down by addition of water and determined by means of 
the hollow prism, as in the case of alum. These are represented by small circles on 
Diagram II. and serve, as before, to establish approximately a curve showing the 
relation between composition and refractive index in supersaturated and strong 
solutions of tartaric acid. 
Table Y^III.—Series of Consecutive Determinations made by Method of Minimum 
Deviation. 
No. 
m. 
11. 
t. 
1 1 
58-489 
1-41672 
o 
19 
' 2 
53■542 
1-40843 
19 
o 
0 
48-908 
1-40092 
19 
4 
44-588 
1-39459 
19 
5 
40-573 
1-38817 
19 
i 6 
36-856 
1-38247 
19 
I 7 
33-427 
1-37728 
19 
1 8 
30-272 
1-37292 
19 j 
i 9 
27-377 
1-36860 
19 
10 
24-729 
1-36470 
19 
! 11 
22-312 
1-36149 
19 
12 
19-842 
1-35789 
1 
(3.) Refractive Indices of Solutions of Sodium Chlorate. 
The refractive index of a saturated solution of sodium chlorate was found as 
follows :— 
/X. 
! 
1-38754 
1-38634 
i 
1 
16-2 By total reflection. 
19 By minimum delation. 
1 
Supersaturated and strong solutions were next examined by the total reflection 
method, as in the preceding examples. 
In Series I., 20 cub. centims. of a solution containing I3T4I grammes of sodium 
chlorate were jflaced in the trough and examined with a totally reflecting prism of 
angle 44° 51', and index I •51704, and diluted down by successive additions of 2 cub. 
centims. of water. The results are given in Table IX., and are represented by dots 
in Diagram III. 
In Series II., 10 cub. centims. ol a supersaturated solution containing 8‘026 grammes 
