Pierre Joseph Macquer
Elements of the Theory and Practice of Chymistry, 5th ed
Published by Good Press, 2021
EAN 4057664591579
Table of Contents
ELEMENTS OF THE PRACTICE of CHYMISTRY ;
ELEMENTS
THEORY of CHYMISTRY.
CHAP. I.
Of the Principles of Bodies.
The object and principal end of Chymistry, is to separate the different substances that enter into the composition of bodies; to examine each of them apart; to discover their properties and relations; to decompose, if possible, those very substances; to compare them together, and combine them with others; to re-unite them again into one body, so as to reproduce the original compound with all its properties; or even to produce new compounds that never existed among the works of nature, from mixtures of other matters differently combined.
But this Analysis, or Decomposition, of bodies is finite; we being unable to carry it beyond a certain limit. In whatever way we attempt to go further, we are always stopped by substances in which we can produce no change, which will not admit of being resolved into others, and which stand as so many firm barriers obstructing our progress.
To these substances we may, in my opinion, give the title of Principles or Elements: at least, with regard to us, they are really such. Of this sort the principal are Earth, Water, Air, and Fire. For though there is ground to believe that these are not the primary component parts, or the most simple elements, of matter; yet, as we know by experience, that our senses cannot possibly discover the principles of which they are composed, it seems more reasonable to fix upon them, and consider them as simple homogeneous bodies, and the principles of the rest, than to fatigue our minds with vain conjectures about the parts or elements of which they may consist; seeing there is no criterion by which we can know whether we have hit upon the truth, or whether the notions we have formed are mere fancies. We shall therefore consider these four substances as the principles or elements of all the various compounds which nature presents to our inquiries: because, of all those we have as yet discovered, they are in fact the most simple; and because all our decompositions, all our experiments on other bodies, plainly prove that they are at last resolvable into these primary parts.
These principles do not enter in the same proportion into all bodies: there are even some mixts in the composition of which this or that particular principle is not to be found. Thus Air and Water seem to be wholly excluded from the texture of Metals; at least all the experiments that have hitherto been made on them seem to confirm this opinion.
The substances composed immediately of these first Elements we shall call secondary Principles; because in reality their several combinations with each other, the interchangeable coalitions that take place between them, constitute the different natures of all other bodies; which, as they result from the union both of primary and secondary principles, are properly entitled to the name of Compounds or Mixts.
Before we enter upon the examination of Compound Substances, it is necessary to consider with some attention the most Simple ones, or our four first principles, in order to discover their chief properties.
SECTION I.
Of Air.
Air is that Fluid which we constantly breathe, and which surrounds the whole surface of the terrestrial globe. Being heavy, like all other bodies, it penetrates into all places that are not either absolutely inaccessible, or filled with some other body heavier than itself. Its principal property is to be susceptible of condensation and rarefaction; so that the very same quantity of Air may occupy a much greater, or a much smaller space, according to the different state it is in. Heat and cold, or, if you will, the presence and the absence of the particles of Fire, are the most usual causes, and indeed the measures, of its