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I will require, for example, again and again, to insist upon the existence of certain laws of quantitative chemical combination, which every workman, whether burning fuel, consuming smoke, reducing metallic ores, gilding pins, working a telegraph, bleaching a piece of linen, dyeing a feather, distilling an acid, making a square of soap, tanning a piece of skin, or executing a hundred other things, should obey. But I will briefly and dogmatically announce those laws as things certain, leaving it to my accomplished colleague, the Professor of Chemistry (who so largely possesses the power over arithmetical numbers hereditary in the family of the Gregories), to discuss critically the grounds on which chemists acknowledge the existence of combining ratios or equivalents, and to explain what arguments can be urged, in defence or denial of the existence of atoms, and the vindication of an atomic theory. To him will also belong; the scientific definition of an element, a metal, a metalloid, an acid, a base, a salt, a radical, a basyle, and many other things, which I shall refer to as acknowledged chemical existences.
The wonderful laws every day additionally beautifying the face of organic chemistry, it will be his, I could almost say, enviable duty to expound. For me, starch will be simply starch, and sugar, sugar, alcohol, alcohol, and vinegar, vinegar. Dr Gregory will retain the privilege of expatiating on these, and all other such compounds as members of curiously related series; and of discussing all the marvellous principles of arrangement, which men of genius have discovered to connect together these common things. Moreover, I am certain, that after Dr Gregory has, to the extent of his great learning on such subjects, lectured to the full on carbon, hydrogen, oxygen, sulphur, and phosphorus, he will still leave ample materials for me as expounder of the economics of combustion. His treatment of the metals will pave the way for my metallurgical discussions; his discussion of chlorine for that of bleaching, and so on with other chemical arts.
Again, I cannot discuss the uses of fuel without continually referring to the thermometer. But I shall accept it as an accredited, and for practical purposes, a perfect instrument. The nature of heat; the laws of conduction; the laws of expansion; the question of the relation of the quantity of heat to its intensity; of the extent to which, in any sense, we can measure heat; the conditions essential to a perfect heat-measurer, and the many other problems of the science of thermotics, which have in their issues, the most important
