j 7 S C H E M I 
ever, be remarked, that they ufe the word principle in a 
different- fenfe from that adopted by the ancient philofo- 
phers. For Ariftotle and Plato did not regard any fub- 
ftances as principles, but fuch as are too minute to be 
perceived by the fienfes ; and form, by their alfemblage, 
bodies fomewhat lefs fimple, which are within the fphere 
of perception, and were by them called elements ; a name 
itili retained, and applied in the fame fenfe. Thefe are 
what other philofophers have called atoms, or monades. 
But c'nemifts, not chooiing to enter rafhly into fpecula- 
tions of fuch fubtlety, apply the term principle in gene¬ 
ral to all bodies, whether fimple, or more or lefs com¬ 
pounded, which they obtain in their analyfes. Yet as 
principles, confidered in this point of view, are very dif¬ 
ferent from each other, they have divided them- into 
■proximate and remote principles. The firft are fuch as 
are feparated by a firlt analyfis, and may themfelves be 
compofed of others; as for example, in decompofing a 
vegetable fubftance, oils, mucilages, falts, and colouring 
matter, are feparated from each other, and are the proxi¬ 
mate principles from which, by new operations, other 
principles may be had. By remote principles they mean 
fubftances more fimple than the former, and which enter 
into their compofition, fince they may be obtained from 
them. Thus mucilage, which is a proximate principle 
of plants, affords, by a new analyfis, oil, water, and 
earth, which are the remote principles of the plant. 
Other names have alfo been given to thefe two orders 
of principles, fuch as principiated principles applied to 
thofe before called proximate, and principiant principles 
to thofe called remote. Thefe words imply, that the lirft 
are compofed of other principles, and that the laft are 
fuch as ferve to form or conftitute others more com¬ 
pounded. Some chemifts, for greater accuracy of difi- 
tindion, admit feveral orders of principles. They call 
the molt fimple, or thofe which cannot be farther de- 
compofed by the name of primitive, primary, or firff 
principles. Principles compofed of the molt fimple kind 
united are called lecondary, or principles of the fecond 
order. Principles of the third order or ternary, are com¬ 
pofed of thefe laft; and laftly, thofe into the formation 
of which principles of the third order enter, are termed 
quaternary, or principles of the fourth order, &c. 
The number of elements has not been always the fame 
among philofophers. Some, with Thales the Milelian, 
who w-as placed in the rank of the feven fages of Greece, 
on account of his uncommon acquifitions in knowledge, 
and who, according to Cicero, was the firft of the Gre¬ 
cians who applied himfelf to natural philofophy, have 
regarded water as the principle of all things. Accord¬ 
ing to Anaximenes, air occupies this firft place ; and he 
did not fcruple to deify this element, on account of its 
great importance. Some conferred this privilege on fire ; 
others beftowed the chief dignity upon the earth ; the 
leader of whom was Anaximander, the difciple of Thales, 
and mafter of Anaximenes. Every one found reafons to 
fupport his owm opinion ; but, as the true method of 
conducing chemical and philofophical inquiries was not 
then known, we can only efteem thefe early notions as 
fpeculations, void of all foundation. About three cen¬ 
turies after the time of thefe philofophers, Empedocles, 
a phyfician of Agrigentum, thinking that the fimplicity 
of the four fubftances contended for as the principle of 
all things to be equal, united their opinions, by admit¬ 
ting of four elements, fire, air, earth, and water. In the 
fucceeding age, Ariftotle and Zeno adopted this opinion 
of Empedocles. When we refled on the reafons that 
may have engaged thefe philofophers to regard fire, air, 
earth, and water, as elements, we are tempted to believe 
that it was not fo much in confequence of the accurate 
knowledge they could have acquired concerning thefe 
bodies, as in confideration of the magnitude or quantity 
of them, and the conllancy or invariability of their pro¬ 
perties. Fire exifts every where, and its effects are always 
a 
S T R Y, 
the fame. Our globe is fuiYOUnded by a mafs of air, the 
quantity and etfential properties of which do not feem 
iubjed to variation. Water is prefented to obfervation 
on the furface of the globe, in an immenfe mafs, that fills 
up or conceals its abyffes or cavities. And, laftly, the 
globe itfelf, whofe volume far exceeds that of all the 
creatures that inhabit it, feems to be formed of a fblid 
matter, little fubjed to change, capable of fixing or ferv- 
ing as a bale for the other elements. It appears, there¬ 
fore, that it was from confiderations, founded on the 
bulk and apparent immutability of thefe bodies, that the 
early fages were induced to regard them as the materials 
ufed by nature in the formation of all other beings. 
The peripatetic dodrine which prevailed in the lchools, 
preferved the Ariftotelian diftindion of elements, till the 
fixteenth century. At that period, the fed of chemifts, 
which began to prevail againft the others, admitted a 
new' divifion of primary fubftances. Paracelfus, who was 
more of the artift than of the philofopher, drew imme¬ 
diate inferences from the refults of his operations, and 
acknowledged five principles; fpirit, or mercury; phlegm, 
or water; fait; fulphur, or oil; and earth. By fpirit, or 
mercury, he underftood every volatile and odorous fub¬ 
ftance, though fimplicity is far from being a conftant 
attendant on thefe properties. Water, or phlegm, com¬ 
prehended in his fyftem, all the aqueous and infipid pro- 
duds, and is liable to the fame objedion with refped to 
its pretended fimplicity. The w'ord fulphur, or oil, de¬ 
noted all inflammable and liquid fubftances, and con- 
fequently a great number of bodies more or lefs com¬ 
pounded, as the fat and efiential oils, &c. By fait, he 
indicated every dry fubftance poflefling tafte and folubi- 
lity, qualities that belong to a great number of com¬ 
pounds. Laftly, the word earth was applied in the doc¬ 
trine of Paracelfus, to the dry, fixed, and infipid refidues 
of operations, all of which are now known to differ ex¬ 
ceedingly from each other. 
Beecher, a chernift, who has treated his fubjed in the 
molt philofophical manner, was aware of the objections 
that might be urged againft the doctrine of Paracelfus, 
and, from a convidion of its infufficiency, he took an¬ 
other method of arriving at the elements of bodies. He 
firft diftinguifhed two principles very different from each 
other, humidity and drynefs, water and earth. He di¬ 
vided this laft into three fpecies ; namely, the vitrifiable, 
inflammable, and mercurial. Vitrifiable earth, accord¬ 
ing to him, was that which alone poffefled the greateft 
immutability; but, when mixed with fome faline earth, 
was capable of forming the molt perfed glafs. He like- 
wife attributed to it the property of rendering the com¬ 
binations into which it entered folid, and little fubjed to 
change. The inflammable earth was known by the com- 
bultibility of the combinations it enters into. Beecher 
regarded it as the caufe of fmell, colour, and volatility. 
The mercurial earth he fuppofed to confift in mercury, 
arlenic, marine acid, See. and its peculiar character was 
that of giving a very confiderable volatility and fpecific 
gravity to the compounds in which it exifted, two in- 
confiftent and oppolite qualities. Stahl adopted, and 
commented on, the doctrine of Beecher. He regarded 
the inflammable earth as fire fixed in bodies, and gave it 
the name of phlogifton. He could not fucceed in de- 
monftrating the exiftence of mercurial earth, and there 
has nothing been done to this day, which at all efta- 
blilhes it. Stahl paid the greateft attention to combina¬ 
tions containing earth, water, and efpecially phlogifton ; 
but he has faid nothing concerning air, which Hales, 
nearly at the fame period, proved to be a principal agent 
in chemical phenomena. From the time of Beecher and 
Stahl to the prelent, no change has been made by che¬ 
mifts in the dodrine of the elements laid dow>n by the 
ancient philofophers. Like Empedocles, they have ac¬ 
knowledged four elements, and have confidered each in 
two different Hates, i. As free, or initiated; in the 
large 
