CHAPTER I.

OF THE PHYSICAL SCIENCES.

755. THE ground and relations of Physics, as a branch of Physiology and of universal science, having been already pointed out and distinguished; it belongs, in the next place, to the present Outline to investigate the natural species of Physical Science according to universal analogy, and to reconcile them with those current or established forms of science from which they take their denominations; justifying, at the same time, our analogical theory by the coincidences of these acknowledged sciences, and the analogies of particulars and practice.

756. It is true, we might have proceeded in our analysis to develope the subordinate sciences without end, for the sciences are as numberless as the arts: but, on this account, also, it becomes necessary that some point should be established at which analysis should terminate; and since, in reconciling our arrangements with the established

or ostensible sciences and language, we are bound to take the latter as we find them, this point may reasonably be where analogy, in name and nature, becomes lost between the strict distributions of natural science and the denominations of the arbitrary and accepted sciences.

Here,

757. Accordingly, our present position is precisely that at which the denominations of the current and accepted sciences accord with the natural distributions to which we have assigned them; beyond which, analogy and coincidence become either defective, obscure, or lost. therefore, our analysis should terminate; and, as the denominations of the established sciences denote both theory and practice, while in our previous distribution we have regarded science as purely theoretic, we may now, also, further justify or confirm our theoretic distributions by the coincidences of particulars and practice.

758. Now, the essential difference of theory and practice is that the first rests upon universals, and the latter upon particulars, whence the end of theory is the beginning of practice, and, vice versá, the end of practice is introductive, or inductive, of theory; and, as there is no absolute particularity or universality, we may not only establish both theory and practice arbitrarily between these relative extremes, but we may also unite them with the same latitude.

759. Hence, the various arbitrary foundations

of the sciences, which sprung originally from imperfect inductions or generalizations of particular knowledge and practice, and the confounding therein of science, or theory, with art, or practice; and hence unavoidable anomalies, renitencies, and discrepancies, will arise in the attempt to reconcile the established sciences with the strict regulations and arrangements of a universal theory.

760. And, as particulars are infinite, and practice depends upon particulars, while our knowledge of particulars is necessarily deficient, and practice is proportionate to this knowledge, it follows, also, that the practical confirmations of theory will be proportionately limited, and far from complete and perfect.

761. Under the view, therefore, of harmonising theory with practice, or reason with experience, and of reconciling our specific arrangements with the corresponding acknowledged sciences, we commence with the physical branch of physiological

science.

762. The Physical Sciences, then, have this in common, that their principal relations are material or external; and, in treating of them specifically, we must resort to material nature and experience for those analogical facts which in the higher genera, and in the universals of science, we take from the source of reason and reflection only; according to the universal forms of which we have already distributed these sciences under the

three specific heads of Chemistry, Botany, and Medicine.

763. These correspond to the three kingdoms of the Natural Philosophers, denominated the mineral, vegetal, and animal kingdoms; and of these we will treat, first, of Chemistry, which is the most material, physical, and external of the three we say external, for, however remote from universality a science may be, it still partakes, as a whole and in its parts, of those extremes and mean which are the inseparable relations of science.

764. Physical effects are commonly divided into chemical and mechanical, - yet, indeed, all physical effect or motion is, primarily or in principle, chemical; and all mechanical effect or motion is secondary or dependent on power, or an agent which is not mechanical; and thus the whole of Dynamics, and all Mechanics, depend upon chemical agency: but this, as a doctrine, belongs to Ontology, and connects Physics with Mechanics.