Consequently, since phosphoric acid results from the phosphine
in crude acetylene when the gas is passed through aqua regia, silica may
be found on subsequently evaporating the latter. But this, silica, he
found, was derived from the glass and not through the oxidation of
silicon compounds in the acetylene. It is possible that some of the
earlier observers of the occurrence of silicon compounds in crude
acetylene may have been misled by the solution of silica from the glass
vessels used in their investigations. The improbability of recognisable
quantities of silicon compounds occurring in acetylene in any ordinary
conditions of generation is demonstrated by a recent study by Fraenkel of
the composition of the deposit produced on reflectors exposed to the
products of combustion of a sample of acetylene which afforded a haze
when burnt. The deposit contained 51.07 per cent. of phosphoric acid, but
no silica. The gas itself contained from 0.0672 to 0.0837 per cent. by
volume of phosphine.
PURIFYING MATERIALS.--When acetylene first began to be used as a domestic
illuminant, most generator builders denied that there was any need for
the removal of these carbide impurities from the gas, some going so far
as to assert that their apparatus yielded so much purer an acetylene than
other plant, where purification might be desirable, that an addition of a
special purifier was wholly unnecessary.
Pages:
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344