Methane (marsh-gas), owing to its comparatively high flame temperature,
and to the fact that it has an intrinsic, if small, illuminating power,
is a better diluent of acetylene than carbon monoxide or hydrogen, in
that it preserves to a greater extent the illuminative value of the
acetylene.
Actually comparisons of the effect of additions of various proportions of
a richly illuminating gas, such as acetylene, on the illuminative value
of a gas which has little or no inherent illuminating power, are largely
vitiated by the want of any systematic method for arriving at the
representative illuminative value of any illuminating gas. A statement
that the illuminating power of a gas is _x_ candles is, strictly
speaking, incomplete, unless it is supplemented by the information that
the gas during testing was burnt (1) in a specified type of burner, and
(2) either at a specified fixed rate of consumption or so as to afford a
light of a certain specified intensity. There is no general agreement,
even in respect of the statutory testing of the illuminating power of
coal-gas supplies, as to the observance of uniform conditions of burning
of the gas under test, and in regard to more highly illuminating gases
there is even greater diversity of conditions.
Pages:
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622