ardly to be found in the escaping gases.

These experiments are of the gravest import, as they show more clearly
than has ever been done before the absolute necessity for special and
perfect ventilation where coal gas is employed for the illumination of
our dwelling rooms.

When coal gas was first employed during the early part of this century
as an illuminating agent, the low pitch of the old fashioned rooms,
and the excess of impurities in the gas, rendered it imperative that
the products of combustion of the sulphur-laden gas should be
conducted from the apartment, and for this purpose arrangements of
tubes with funnel shaped openings were suspended over the burners. The
noxious gases were thus conveyed either to the flue or open air; but
this type of ventilator was unsightly in the extreme, and some few
attempts were made to replace it by a more elegant arrangement, as in
the ventilating lamp invented by Faraday, and in the adaptation of the
same principle by Mr. I.O.N. Rutter, who strove for many years to
direct attention to the necessity of removing the products of
combustion from the room. But with the increase of the gas industry,
the methods for purifying the coal gas became gradually more and more
perfect, while the rooms in the modern houses were made more lofty;
and the products of combustion being mixed with a larger volume of
air, and not containing so many deleterious constituents, became, if
not much less noxious, at all events less perceptible to the nose. As
soon as this point was reached, the ventilating tubes were discarded,
and from that day to this the air of our dwelling rooms has been
contaminated by illuminants, with hardly an effort to alleviate the
effect produced upon health. I say "hardly an effort," for the Messrs.
Boyle tried, by their concentric tube ventilators, to meet the
difficulty, while Mr. De la Garde and Mr. Hammond have each
constructed lamps more or less on the principle of the Rutter lamp;
but either from their being somewhat unsightly, or from their
diminishing the amount of light given out, none of them have met with
any degree of success. In places of public entertainment, where large
quantities of coal gas are consumed for illuminating purposes, the
absolute necessity for special ventilation gave rise to the "sun
burner," with its ventilating shaft. This, however, gives but a very
poor illuminating power per cubic foot of gas consumed, due partly to
the cooling of the fla