[17] These results were obtained when using ammonium sulphocyanate, and
cannot be explained by the presence of such impurities as chlorides, &c.
[18] Multiply the _standard_ by 1000, and dilute 100 c.c. of the
standard solution to the resulting number of c.c. Thus, with a solution
of a standard .495, dilute 100 c.c. to 495 c.c., using, of course,
distilled water.
[19] HNa_{2}AsO_{4} + 3AgNO_{3} = Ag_{3}AsO_{4} + HNO_{3} + 2NaNO_{3}.
[20] SiO_{2} + Na_{2}CO_{3} = CO_{2} + Na_{2}SiO_{3}
SiO_{2} + 2NaHCO_{3} = 2CO_{2} + Na_{2}SiO_{3} + H_{2}O.
[21] PbO + SiO_{2} = PbSiO_{3}
[22] Here and elsewhere in this article when a flux is spoken of as soda
the bicarbonate is meant.
[23] See the description of the process commencing on p. 98 and the
explanatory remarks on p. 110.
[24] Percy, _Metallurgy of Silver and Gold_, p. 258.
[25] "Limits of Accuracy attained in Gold-bullion Assay," _Trans. Chem.
Soc._, 1893.
[26] "Assaying and Hall-marking at the Chester Assay Office." W.F. Lowe.
_Journ. Soc. Chem. Industry_, Sept. 1889.
[27] Fine or pure gold is 24 carat. Nine carat gold therefore contains 9
parts of gold in 24 of the alloy; eighteen carat gold contains 18 parts
of gold in 24; and so on.
[28] The mouth of the flask must not have a rim around it.
[29] See "Assaying and Hall-marking at the Chester Assay Office," by
W.
Pages:
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334