V O L U M E 21, NO. 3, M A R C H 1 9 4 9 relationships by the a~iplicati~iii of the lair i ) f mixtures. This is particularly disappointing. for such a procedure would enable an assayer to arrive at thr ptLrcentage composition of gold-silver alloy beads n-ithout the operations of inquartation, parting, and annealing, n-hich are mucli niore time-consuming and involve a greater risk of loss than would t,he type of determination under examination. However, theoretically, an empirical curve relating true composition to values experinlentall? determined, cveii though they are not stoichiometric, should enable thc olijective to be realized. Such a curve has been constructed in thtw lahoratories and this phase will be reported on later. Chamot and Mason ( 3 ) state that “if the substance call l i t , made to take the form of a sphere, the results may Le highly accurate.” Blank and Killard (1 ), cit,ing the same authoritit,. (4-S), state flatly that microdensity determinations, which dcpend upon the same data, cannot he made accurately by t h w . methods. Evidence obtained in theye laboratories s h o m that results are stoichiomrtric in the case of pure noble metals but i t has not b t ~ r r i posaililc. so i’:ii.. t o iihtain comnlun1)le rcsults n.itti
417
gold-sliver alloys:. This paper attempts to prove that, observed discrepancies are not connected with weight determination or errors i n mcnsuration. 4CKNOWLEDGhlENTS
The assktance of advanced students, particularly Thos. S. Hurkhalter, H. K. I,ewi\, and W. R. Reed, is gratefully acknowlr (1 gcd. L I n x i w t t E CIT~:I) ; l i Hlaiik, E. b’.. and Willard,
M.L., . I .
(’hem. Education, 10, 109-12
(1933).
2) C‘hamot and Mason, “Handhook of Chemical S l i c r o s c o p y , ” Vol. I. pp. 399-402, New York, John W i l e s & Sons, 1930. (3) Z b i d . , pp. 4 2 2 , 1 2 3 . (4) G o l d s c h m i d t . Victor, 2. ana2. Chem., 1 6 , 434 (1877). ( 5 ) I b i d . , 1 6 , 449 (1877). (6) Lunde, Gulbrand. Mikrochemie. 5, 16. 102 (1927). I
Spectrographic Determination of Phosphorus and Metals in lubricating Oils, Using a Porois Cip Electrode i.(;. G - i S s \ l A N h ~ N I W. ) I
