Copper and zinc in W-1 have been determined using a Jarrell-Ash Model 82-360 atomic absorption flame photometer. The results are 116 ± 3 ppm for Cu and 86 ± 3 ppm for Zn. (Errors are expressed by the probable error of the mean of four determinations.) These results compare favorably with the recently reported values, thereby suggesting that the background absorption effect is practically negligible in these concentration ranges. Net sample consumption was about 20 mg of W-1 powder per
element.
