Acetylene, the Principles of Its Generation and Use | Page 6

they sterilise a larger volume of
air. All the air which is needed to support combustion, as well as the
excess of air which actually passes through the burner tube and flame
in incandescent burners, is obviously sterilised; but so also is the much
larger volume of air which, by virtue of the up-current due to the heat
of the flame, is brought into anything like close proximity with the light.
The electric glow-lamp, and the most popular and economical modern
enclosed electric arc-lamp, sterilise only the much smaller volume of
air which is brought into direct contact with their glass bulbs. Moreover,
when large numbers of persons are congregated in insufficiently
ventilated buildings--and many public rooms are insufficiently
ventilated--the air becomes nauseous to inspire and positively
detrimental to the health of delicate people, by reason of the human
effluvia which arise from soiled raiment and uncleansed or unhealthy
bodies, long before the proportion of carbonic acid by itself is high
enough to be objectionable. Thus a certain proportion of carbonic acid
coming from human lungs and skin is more harmful than the same
proportion of carbonic acid derived from the combustion of gas or oil.
Hence acetylene and flame illuminants generally have the valuable
hygienic advantages over electric lighting, not only of killing a far
larger number of the micro-organisms that may be present in the air,
but, by virtue of their naked flames, of burning up and destroying a
considerable quantity of the aforesaid odoriferous matter, thus relieving
the nose and materially assisting in the prevention of that lassitude and
anæmia occasionally follow the constant inspiration of air rendered
foul by human exhalations.
The more important advantages of acetylene as an illuminant have now
been indicated, and it remains to discuss the cost of acetylene lighting
in comparison with other modes of procuring artificial light. At the
outset it may be stated that a very much greater reduction in the price of
calcium carbide--from which acetylene is produced--than is likely to
ensue under the present methods and conditions of manufacture will be
required to make acetylene lighting as cheap as ordinary gas lighting in
towns in this country, provided incandescent burners are used for the
gas. On the score of cheapness (and of convenience, unless the

acetylene were delivered to the premises from some central generating
station) acetylene cannot compete as an illuminant with coal-gas where
the latter costs, say, not more than 5s. per 1000 cubic feet, if only
reasonable attention is given to the gas-burners, and at least a quarter of
them are on the incandescent system. If, on the other hand, coal-gas is
misused and wasted through the employment only of interior or
worn-out flat-flame burners, while the best types of burner are used for
acetylene, the latter gas may prove as cheap for lighting as coal-gas at,
say, 2s. 6d. per 1000 cubic feet (and be far better hygienically);
whereas, contrariwise, if coal-gas is used only with good and properly
maintained incandescent burners, it may cost over 10s. per 1000 cubic
feet, and be cheaper than acetylene burned in good burners (and as
good from the hygienic standpoint). More precise figures on the
relative costs of coal-gas lighting and acetylene lighting are given in
the tabular statement at the close of this chapter.
With regard to electric lighting it is somewhat difficult to lay down a
fair basis of comparison, owing to the wide variations in the cost of
current, and in the efficiency of lamps, and to the undoubted hygienic
and aesthetic claims of electric lighting to precedence. But in towns in
this country where there is a public electricity supply, electric lighting
will be used rather than acetylene for the same reasons that it is
preferred to coal-gas. Cost is only a secondary consideration in such
cases, and where coal-gas is reasonably cheap, and nevertheless gives
place to electric lighting, acetylene clearly cannot hope to supplant the
latter. [Footnote: Where, however, as is frequently the case with small
public electricity-supply works, the voltage of the supply varies greatly,
the fluctuations in the light of the lamps, and the frequent destruction of
fuses and lamps, are such manifest inconveniences that acetylene is in
fact now being generally preferred to electric lighting in such
circumstances.] But where current cannot be had from an
electricity-supply undertaking, and it is a question, in the event of
electric lighting being adopted, of generating current by driving a
dynamo, either by means of a gas-engine supplied from public
gas-mains, by means of a special boiler installation, or by means of an
oil-engine or of a power gas-plant and gas-engine, the claims of
acetylene to preference are very strong. An important factor in the
estimation of the relative advantages of electricity and acetylene in

such cases is the cost of labour