pretend to the naturally best or perfect distribution of chemical substances, our knowledge of the particulars of which must ever fall short of perfect inductions: every firm step of experience will, however, advance the generalogy of nature, draw nearer to universal forms, and improve and strengthen coincidence and analogy.

SECTION III.

790. Secondly, of the CHEMISTRY OF LIQUIDS, which comprehends that medial state, or form of substances, in which Chemistry exhibits its principal effects. Solids require to be brought into this state before they can combine, or exert those elective affinities, as they are called, by which decompositions and new combinations are produced to infinity.

791. Fire, the chemical agent, has at all times been regarded as the principle of fluidity, which is the medial effect of the concurrence of the elementary agent and patient.

792. Of substances naturally liquid there are three principal, the Oleous, the Aqueous, and the Spirituous, of which the first verge upon solidity, and the last upon elasticity. Of the first, the extreme examples are the animal fat Oils, &c., nearest to solidity; and of the last, on the other extreme, are the liquids called Ethers, which

border on the elastic state of substances; and each of these is capable of fixation and volatilization, or of the solid and elastic states.

793. Further, of Oleous liquids, we have the fixed animal Fat Oils; the gelatinous, or Drying Oils; and the resinous, essential, or Volatile Oils. Of Spirituous liquids, on the opposite extreme, there are Acetose Spirits; vinous or Sweet Spirits, or alcohol; and Oxymelous Spirits, or Ethers, in which the sweet and acid spirit are conjoined.

794. Between Oleous and Spirituous liquids is Water, pre-eminent among liquids, and central among chemical substances, being the mean of the medial or liquid form, in the constitution and effect of which the elementary agent and patient are in equal concurrence; which, at 32° of Fahrenheit's thermometer, becomes solid ice, and at 212°, elastic steam.

795. Of all natural substances, Water is the most abundantly diffused, it being also the chief agent in the chemistry of nature, and the most essential in that of art, if it be not even the matrix and medium whereby all other chemical substances are produced or evolved. Such, at least, has been which is supported by

a very antient doctrine, modern discoveries; and certain it is that water performs a grand part in the economy of nature throughout the mineral, vegetal, and animal kingdoms.

SECTION IV.

796. Thirdly, and lastly in our distribution, is the CHEMISTRY OF ELASTICS; and of these we recognise, first, Vapours, or substances rendered elastic by fire or free caloric; secondly, Airs or Gases permanently elastic by the agency of latent or combined caloric; and, thirdly, if we err not, there is another state of matter even more subtile than the gaseous, in which the chemical elements exhibit themselves in their primary and simplest combinations and concurrence, as active and passive, in Ethereal or Vital fluids.

797. Vapours, Aerials, and Ethereals are, therefore, gradient in the chemistry of Elastics, and the last of them are ultimate in chemical analysis, and intimately allied to the immaterial elements of chemical substances; and as they are final in chemical science, so are they the foundation of the organical or vital sciences.

798. Of the three species of Elastics, the first are Vapours; and of these there are the solid kind, or dry vapours, whence sublimation; the liquid kind, or humid vapours, whence distillation; and elastic vapours, such as are the moisture of a clear atmosphere, steam at a high temperature, effluvia, &c. Of all which, and of all evaporization, fire, heat, or caloric, is the agent.

799. Secondly, of Gases, or permanent Elastics,

which are medial and principal in this branch of Chemistry, there are the Combustible, Inflammable, or Hydrogenous Gases—those which support combustion, or Oxygenous Gases. There are others, also, of an intermediate kind, which are products of, and destroy combustion, and such are Carbonic and Azotic, or Nitrogen Gases; all of which agree in being resoluble into caloric, or an Active principle, and a base, or Passive principle; and it is to the essential variety and formal relations of the original Agent and Patient that we attribute the diversity of the Gases.

800. Accordingly, we hold Nitrogen or Azotic Gas, which constitutes four-fifths of the atmosphere we breathe, to be the first, simplest, and most elementary compound of the two former, proceeding from, and participating, their active and reactive powers according to chemical election; and comprising elementarily the true tria prima of the

chemist.

801. Of the manner in which these new and admirable products of this science result from, and enter into, the constitution of solids and liquids, we shall yet have occasion to speak, and they hold the principal place in most modern treatises of scientific and technical Chemistry.

802. Modern Chemistry has resolved the Solids and Liquids of nature into Elastics, and has distinguished these again into many different kinds. It has gone still further, and resolved these into

their unknown bases. It has also demonstrated the immense sensible and latent powers of these latter. The utmost praise is indeed due to the skill, acuteness, and industry of modern Experimentalists exhibited in the resolution and composition, or analysis and synthesis, of substances previously deemed simple and elementary, to the great obstruction of chemical knowledge. Yet is the way merely opened, and much remains to be done practically ere the phenomena of this interesting portion of nature can be perfectly reconciled with the theoretic demands of reason and universal science.

803. Thirdly, and finally, of Ethereals, which comprehend those subtle matters, the effects of which are apparent in Light, Heat, Motion, &c.: by the latter of which Chemistry is connected, on the one hand, with mechanical science; and by the former, on the other hand, with sensible science.

804. Experience is so recent, in this elevated department of Chemistry, as hardly yet to have furnished particulars sufficiently wide and various for a basis to its universal relations; yet even here we are not destitute of coincidence: and, from the present enterprising spirit and ingenuity of experimental philosophers, we may reasonably hope an early determination of their true doctrine and analogy.

805. Accordingly, Ethereals appear to be of