2 milligrammes
of PH_3 per litre or 14.13 grains per cubic foot (Polis); but this sample
dated from 1897. Eitner and Keppeler record the minimum proportion of
phosphorus, calculated as PH_3, found in crude acetylene, as 0.45
milligramme per litre, and the maximum as 0.89 milligramme per litre; in
English terms these figures are 0.2 and 0.4 grain per cubic foot. On an
average, however, British and Continental carbide of the present day may
be said to give a gas containing 0.61 milligramme of phosphorus
calculated as PH_3 per litre and 0.75 milligramme of sulphur calculated
as H_2S. In other units these figures are equal to 0.27 grain of PH_3 and
0.33 grain of H_2S per 1 cubic foot, or to 0.041 per cent. by volume of
PH_3 and 0.052 per cent. of H_2S. Yields of phosphorus and sulphur much
higher than these will be found in the journals and books, but such
analytical data were usually obtained in the years 1896-99, before the
manufacture of calcium carbide had reached its present degree of
systematic control. A commercial specimen of carbide was seen by one of
the authors as late as 1900 which gave an acetylene containing 1.12
milligramme of elementary sulphur per litre, i.
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