As a scientific means for the purposes mentioned, gas is comparatively untried. This assertion may sound somewhat astounding; but I think it is a true one. More than that, even in the crude and unscientific way in which it has most frequently been used up to the present, it has been far from unsuccessful in comparison with electricity or other means of lighting; and in the future it will prove the best and cheapest practical means, although, for effect, glow lamps may be used in palatial dwellings in conjunction with it. It must be remembered that, in laying down a system of artificial lighting, we have to imitate, as well as we can, that most beautiful and perfect natural light which, without our aid, and without even a thought from us, shines regularly every day upon all, in such an immense volume, so perfectly diffused, and in such wonderful chemical combination, that it may safely be said that not one atom of the whole economy of Nature is unaffected by it, and that we and all the animal kingdom, in common with trees and plants, derive health and vigor therefrom. This glorious natural light leaves our best gas, electricity, oil lamp, and all our multiplicity of candles, immeasurably behind. But although we cannot hope to equal, in all its beneficent results, the effects of daylight, or to perfectly replace it, we can more perfectly make the lighting of our homes comfortable (and as little destructive to the eyes and to the general health) by the aid of gas than by any other means. It must also be borne in mind that, in this country at least, we have to fulfill the conditions of artificial lighting under frequent differences of temperature and barometric influence, exaggerated by the manner in which our homes are built; and that for at least nine months of the year we require heat as well as light in our dwellings, and that for the other three months (excepting in some few favored localities) the nights are often chilly, even though the days may be hot. Therefore, independently of any effect produced by the lighting arrangements, there must be widely different effects produced in the temperature and conditions of the air in rooms by influences entirely beyond our control.