I N D UXTRIAL A N D ENGI S E E R I S G CHEXISTRY
786
1701.
15, KO. s
0.610, respectively. We wish to know how much carbon is necessary to remove 70 per cent of the color. On Fig. 2 draw a straight line from l / n = 0.610 to Y = 0.70, and extend this line to the M K axis. The line (extended) cuts the MK axis a t 1.45. Since K = 3, then M = 1.45/3 = 0.483 grams or pounds of carbon per unit volume of solution, depending on what units of mass and volume were used in securing the adsorption data. Before a carbon can be described in terms of K and l / n for any solution, it will be necessary to adopt standards of mass and volume for the carbon and solution, respectively. The author would suggest the adoption of the following systGm for calculating the values of K and l/n. Use the equation Y / M = K(l-Y)1'" where M = fraction of carbon by weight added to the soIution to be decolorized Y = fraction of color removed by the carbon of weight M K and l / n are the constants to be listed in describing the carbon.
% ?
This system has the advantage that the values of K and 1/n as found in the laboratory are applicable to plant calcu-
lations without the use of any converFiion factor. This last should be a matter for some section of the ANERICAN CHEMICAL SOCIETY to take up, presumably the Sugar Division, as it seems the most interested in decolorizing carbons.
Variation of Refractive Index of China Wood Oil with Tempera turel By F. H. Rhodes and H. E. Goldsmith CORNELL UNIVERSITY. ITHACA, N. Y.
HE refractive indices of two samples of [China wood /O 8 6 5 4
/#
MK / 08
07 0.6 0.5 a4
QJO
oil have been determined a t various temperatures. Sample 1 was from a lot of commercially pure China wood oil (from S. C. Gilespie & Sons). Sample 2 was from a portion of China wood oil of known purity brought directly from China by 8. H. Shen, and donated to us for use in this work. The refractive indices were determined by means of a refractometer provided with a water jacket through which water a t a constant temperature was circulated. The instrument was tested with liquids of known refractive indices, and was found to give correct readings. The results obtained were as follows: Temp.
c.
10 20 30 40 FIG.2
However, this may be done more easily. The nomographic chart, Fig. 2, solves the equation Y / M = K ( l - Y)lIn. This equation is the same as X / M = KCIIn, if we express our color as a fraction of the initial color, and let X = Y , for then C = 1-Y. To use this chart, suppose that experiment shows that for the solution in question the values of K and l / n are 3 and
-SAMPLE 1--Refractive Index Difference 1.5196 0.0040 1,5156 0.0039 1,5117 0.0039 1.5078
> > >
--SAMPLE Refractive Index
2---
Difference
> 0.0040 > 0.0040 1.5155 > 0.0039 1.5116 1.5235 1.5195
From these results it is apparent that the refractive index of China wood oil decreases 0.000395 for each increase of 1' C. in the temperature. This result agrees very closely with the value of 0.0004 obtained by Browne2 from the examination of a single sample of oil through a single temperature interval. 1 2
Received May 18, 1923. Chem. N e w s , 114, 123 (1916).
