THE DETERMINATION OF REFRACTIVE INDEX 
245 
Table II. 
LIQUIDS FOR DETERMINATION OF REFRACTIVE INDICES 
OF MINERALS, CRYSTALS, ETC. 
Wright’s Series. 
Bui. 158, Carnegie Institute. 
For indices 
Use mixtures of 
from 
to 
I -450 
1-475 
Petroleum and turpentine. 
1.480 
I -535 
Turpentine and ethylene bromide or turpentine 
and clove oil. 
I -540 
1-635 
Clove oil and alpha-monobromnaphthalene. 
1.640 
1-655 
Alpha-monobromnaphthalene and alpha-mono- 
chlornaphthalene. 
1.66 
1.740 
Alpha-monobromnaphthalene and methylene 
iodide. 
1.740 
1.790 
Sulphur dissolved in methylene iodide. 
1.790 
1.960 
Methylene iodide, antimony iodide, arsenic sul¬ 
phide, antimony sulphide, sulphur. 
This series requires the use of but few liquids and keeps the dispersion of the liquids within 
narrow limits throughout the series. As prepared for use, each one of the series should differ 
from the ne.xt above or below by 0.005. The value of n in each mixture made must first be de¬ 
termined by means of a refractometer. 
Table III. 
MEDIA FOR REFRACTIVE INDEX DETERMINATIONS.^ 
Weighing out and grinding together in a mortar the weights of the substances given in the 
table, a series of eutectics is obtained, each of which will have the refractive index indicated in 
the first column. Checking with a refractometer is unnecessary. 
Refractive 
index. 
Components in grams. 
1.487 
Thymol. . . 
■ 35 
Camphor. . . 
65 
1-505 
Thymol... 
- 67 
( 1 
33 
1-535 
Salol. 
60 
40 
Alpha-naphthyl- 
1-54 
60 
40 
amine 
5 
1-55 
60 
40 
14 
1.56 
60 
40 
t 
24 
1-57 
60 
40 
34 
1-58 
60 
40 
t 
44 
1-59 
60 
40 
60 
1.60 
60 
40 
82 
1.605 
1 i 
. 60 
< ( 
40 
t 
100 
* Merwin, J. Wash. Acad. Sci., 3 (1913), 35. 
