development of infrared procedures. Absorptivities ranging from 5030 to 5635 sq. em. per gram a t 4.59 microns were found as the vibratory time in the Wig-L-Bug amalgamator was decreased from 60 to 30 seconds. Lilrewisc, the 14.08-micron band in calcium carbonate exhibited intensity modulation dependent on the degree of dispersion in the potassium bromide matrix. In this case, however, absorptivity increased with increasing period of agitation. Unless an internal standard exhibits similar response in absorptivity changes upon mixing as the sample constituents, analysis would be further complicated by the use of such a standard.
ACKNOWLEDGMENT
The writer is indebted to Joseph Dzilsliy for assistance with experimental worli and to 13. F. Armendt for the synthesis and purification of 4-methylphthalic and 4-methylisophthalic acids.
(5) Kendall, I). N., ANAL. CHEM.25, 35'2 (1953). (6) Kirkland, J. J., Ibid., 27, 1537 (1955). (7) Padgett, 'AT. &I., 11, Talbert, J. M., Hamner, W. F., J . Chem. Pliys. 26, 959 (1957). (8) Prince, k'. C., Tctlow, I
