The coincidence of the diurnal variation of the compass with the solar influence, deserves particular notice, and will have considerable weight on this subject. That there are many facts which cannot readily be explained by the theory of light, I shall not deny; but in the infancy of this system we may be allowed to hope that future observations may enable us to remove present difficulties. One thing must be admitted, that no theory has heretofore been published relating to magnetism, which has received or seems entitled to much confidence. In your next number I hope to be able to furnish you with further remarks on this subject; but, I have no doubt that philosophy will finally determine that we owe to the solar ray light, heat, electricity, and magnetism. G. GIBBS. _Sunswick, January, 1818._ ART. XXI. _On a new Means of producing Heat and Light, with an Engraving, by J. L. Sullivan, Esq. of Boston._ BOSTON, May 7, 1818. _To Professor Silliman._ SIR, If the following account of a method of using tar and steam as fuel, recently invented by Mr. Samuel Morey, should be found sufficiently interesting to occupy a place in the Journal of Science, I am sensible its usefulness will be much extended through that medium of information. The inventor, not unskilled in chemistry, and aware of the attraction of oxygen for carbon, conceived it practicable to convert the constituents of water into fuel, by means of this affinity. Whatever may be the fact, chemically considered, the operation, in various experiments, promises to afford a convenient method of applying to use several of the most combustible substances, not hitherto employed as fuel. By the process I shall briefly describe, _all carbonaceous fluids_ may be conveniently burnt, and derive great force from their combination with the oxygen and hydrogen gases of water or steam, before or at the moment of ignition. [Illustration: NEW FIRE APPARATUS. Fig. 1. Fig. 2.] A tight vessel, cylindrically shaped, was first employed, containing rosin, connected with a small boiler by a pipe which entered near the bottom, and extended nearly its length, having small apertures, over which were two inverted gutters, inclining or sloping upwards over each other; the upper one longer than the other, intended to detain the steam in the rosin, in its way to the surface. The rosin being heated, _carburetted hydrogen gas_ would issue from the outlet, or pipe, inserted near the top of the vessel, and being ignited, afforded a small blaze, about as large as that of a candle; but, when the steam was allowed to flow, this blaze would instantly shoot out many hundred times its former bulk, to the distance of two or three feet. It is presumed the steam was decomposed, and carburetted hydrogen and carbonic oxide, or carbonic acid, produced as the steam passed, very near the hot bottom of the vessel.