Although we certainly have no reason to complain of the infrequency of attempts in newspapers, &c., as well as in scientific journals, to explain the principles on which electric lighting depends, it does not seem that very clear ideas are entertained on this subject by unscientific persons. Nor is this, perhaps, to be wondered at, when we observe that in nearly all the explanations which have appeared, technical expressions are quite freely used, while those matters about which the general reader especially desires information are passed over as points with which every one is familiar. Now, without going quite so far as to say that there is no exaggeration in the picture presented some time back in _Punch_, of one who asked whether the electric fluid was 'anything like beer, for instance,' I may confidently assert that the very vaguest notions are entertained by nine-tenths of those who hear about the electric light, respecting the nature of electricity. Of course, I am not here referring to the doubts and difficulties of electricians on this subject. It is well known that Faraday, after a life of research into electrical phenomena, said that when he had studied electricity for a few years he thought he understood much, but when he had nearly finished his observational work he found he knew nothing. In the sense in which Faraday spoke, the most advanced students of science must admit that they know nothing about electricity. But the greater number of those who read about the electric light are not familiar even with electrical phenomena, as distinguished from the interpretation of such phenomena. I am satisfied that there is no exaggeration in a passage which appeared recently in the 'Table Talk' of the _Gentleman's Magazine_, describing an account of the electric light as obtained from some new kind of gas, carried in pipes from central reservoirs, and chiefly differing from common gas in this, that the heat resulting from its consumption melted ordinary burners, so that only burners of carbon or platinum could be safely employed. I do not propose here to discuss, or even to describe (in the proper sense of the word) the various methods of electric lighting which have been either used or suggested. What I wish to do is to give a simple explanation of the general principles on which illumination by electricity depends, and to consider the advantages which this method of illumination appears to promise or possess.