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137
In the first place the testings will be uniform throughout the
District, that is to say, at all testing places the same tests will be
made, viz., calorific power, illuminating power, and sulphur, in addition
to sulphuretted hydrogen, and pressure observations, and there
will no longer be any fixed hours of testing.
The illuminating power standard will be 14 candles (section 57),
and it is proposed to use, instead of the candle balance, which is
antiquated, Harcourt's 10-candle Pentane lamp as the standard
light in the photometer (section 59).
The testing places will be the same as the existing ones, but provision
is made for an additional testing place in the Wandsworth
limits in accordance with a previous arrangement (sections 58
and 65).
The pressure still remains at the absurdly low minimum of
eighth-tenths of one inch, but there is no danger of this limit being
reached, as a much greater pressure is required for the supply of
gas (section 60).
Testing for sulphur and sulphuretted hydrogen remain as before
(section 64).
There will be no penalties in connection with the above testings.
The Calorific Power* (section 61).—The new calorific power
standard has been fixed at 136 calories gross, with a margin of about
10 per cent., the minimum being 122 calories gross. If there is
a deficiency on this minimum, the Company is liable to penalties,
which increase with the deficiency. It will be noted that gross
calorific values have been selected as the standard, and this has been
done with the complete acquiescence of the Company.
*Calorific Power.—By a calorie is meant the amount of heat required to
raise the temperature of 1 kilogramme of water 1 degree Centigrade. For
example, a standard of "125 Calories" would mean that the amount of heat
produced by the burning of 1 cubic foot of gas (measured at 60 degrees Fahrenheit
and 30 inches Barometer) must be such as to raise the temperature of
125 kilogrammes of water 1 degree Centigrade, or, taking British Units,
496 lbs. (500 lbs. nearly) of water 1 degree Fahrenheit. The net calorific power
is obtained by subtracting the heat due to the condensation of some of the
steam formed in the calorimeter and to the cooling of the resulting condensed
water from the total observed heat or gross calorific power. In practice tl e
water is measured, not weighed, hence, for practical purposes, 1 litre might
be substituted for 1 kilogramme.
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