p in some respects and the
latter was a three-flame burner suggesting a fleur-de-lis. In this
installation there were 271 Argand burners and 636 cockspurs. Each of
the former "gave a light equal to that of four candles; and each of the
latter, a light equal to two and a quarter of the same candles; making
therefore the total of the gas light a little more than 2500 candles."
The candle to which he refers was a mold candle "of six in the pound"
and its light was considered a standard of luminous intensity when it
was consuming tallow at the rate of 0.4 oz. (175 grains) per hour. Thus
the candle became very early a standard light-source and has persisted
as such (with certain variations in the specifications) until the
present time. However, during recent years other standard light-sources
have been devised.

According to Murdock, the yearly cost of gas-lighting in this initial
case was 600 pounds sterling after allowing generously for interest on
capital invested and depreciation of the apparatus. The cost of
furnishing the same amount of light by means of candles he computed to
be 2000 pounds sterling. This comparison was on the basis of an average
of two hours of artificial lighting per day. On the basis of three hours
of artificial lighting per day, the relative cost of gas-and
candle-lighting was about one to five. Murdock was characteristically
modest in discussing his achievements and his following statement should
be read with the conditions of the year 1808 in mind:

The peculiar softness and clearness of this light with its
almost unvarying intensity, have brought it into great favour
with the work people. And its being free from the inconvenience
and danger, resulting from sparks and frequent snuffing of
candles, is a circumstance of material importance, as tending
to diminish the hazard of fire, to which cotton mills are known
to be exposed.

Although this installation in the mill of Phillips and Lee is the first
one described by Murdock, in reality it is not the first industrial
gas-lighting installation. During the development of gas apparatus at
the Soho works and after his luminous display in 1802, he gradually
extended gas-lighting to all the principal shops. However, this in a
sense was experimental work. Others were applying their knowledge and
ingenuity to the problem of making gas-lighting practicable, but Murdock
has been aptly termed "the father of gas-lighting.