June 3, 1871.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
079 
that was inert and incombustible energetic and com¬ 
bustible,—and further rendering some particular body 
•combustible over and over again. That this is a fair 
representation of the views held by phlogistic chemists 
is readily recognizable by a study of chemical works 
written before the outbreak of the antiphlogistic revolu¬ 
tion. After Lavoisier's challenge, the advocates of 
7phlogiston, striving to make it account for a novel order 
of facts with which it had little or nothing to do, were 
driven to the most incongruous of positions ; for while 
Priestley wrote of inert nitrogen as phlogisticated air, 
Kir wan and others regarded inflammable hydrogen as 
being phlogiston itself in the isolated state. Very dif¬ 
ferent is the view of phlogiston to be gathered from the 
writings of Dr. Watson, for example, who was appointed 
Professor of Chemistry at Cambridge in 1761, became 
Regius Professor of Divinity in 1771, and Bishop of 
Llandaff in 1782. This cultivated divine, indifferent it 
is true to the novel questions by which in less placid 
regions men’s minds were so deeply stirred, amused the 
leisure of his dignified university life by writing 
scholarly accounts of the chemistry it had formerly been 
his province to teach; and in the first volume of his 
well-known ‘Chemical Essays,’ published in 1781, the 
following excellent account of phlogiston is to be 
found:— 
“Notwithstanding all that perhaps can be said upon 
this subject, I am sensible the reader wall still be ready 
lo ask, What is phlogiston ? You do not surely expect 
that chemistry should be able to present you with a 
handful of phlogiston, separated from an inflammable 
body; you may j ust as reasonably demand a handful of 
magnetism, gravity, or electricity to be extracted from a 
magnetic, weighty, or electric body. There are powers 
in nature which cannot otherwise become the objects of 
sense, than by the effects they produce ; and of this kind 
is phlogiston. But the following experiments will tend 
•to render this perplexed subject somewhat more clear. 
“ If you take a piece of sulphur and set it on fire, it 
will burn entirely away, without leaving any ashes or 
yielding any soot. During the burning of the sulphur, 
-a copious vapour, powerfully affecting the organs of sight 
.and smell, is dispersed. Means have been invented for 
-collecting this vapour, and it is found to be a very strong 
acid. The acid thus procured from the burning of sul¬ 
phur, is incapable of being either burned by itself, or of 
•contributing towards the support of fire in other bodies : 
the sulphur, from which it was procured was capable of 
both: there is a remarkable difference, then, between 
the acid procured from the sulphur and the sulphur 
itself. The acid cannot be the only constituent part of 
.sulphur; it is evident that something else must have en¬ 
tered into its composition, by which it was rendered 
capable of combustion. This something is, from its most 
remarkable property, that of rendering a body combusti¬ 
ble, properly enough denominated the food of fire, the 
inflammable principle, the phlogiston .This inflam¬ 
mable principle, or phlogiston, is not one thing in ani¬ 
mals, another in vegetables, another in minerals; it is 
.absolutely the same in them all.This identity of 
phlogiston may be proved from a variety of decisive ex¬ 
periments ; I will select a few, which may at the same 
time confirm what has been advanced concerning the 
.•constituent parts of sulphur. 
“ From the analysis or decomposition of sulphur 
• effected by burning, we have concluded that the consti¬ 
tuent parts of sulphur are two—an acid which may be 
collected, and an inflammable principle which is dispersed. 
If the reader has yet acquired any real taste for chemical 
truths, he "will wash to see this analysis confirmed by 
. synthesis; that is, in common language, he will wish to 
.see sulphur actually made by combining its acid with an 
inflammable principle. It seldom happens that chemists 
can reproduce the original bodies, though they combine 
together all the principles into which they have analysed 
.them;.in the instance, however, before us, the 
reproduction of the original substance will be found 
complete. 
“As the inflammable principle cannot be obtained in 
a palpable form separate from all other bodies, the only 
method by which we can attempt to unite it with the 
acid of sulphur must be by presenting to that acid some 
substance in which it is contained. Charcoal is such a 
substance; and by distilling powdered charcoal and the 
acid of sulphur together, we can procure a true yellow 
sulphur, in nowise to be distinguished from common 
sulphur. This sulplmr is formed from the union of the 
acid with the phlogiston of the charcoal; and the char¬ 
coal may by this means be so entirely robbed of its phlo¬ 
giston, that it will be reduced to ashes, as if it had been 
burned. 
“ I will in this place, by way of further illustration of 
the term phlogiston, add a word or two concerning the 
necessity of its union with a metallic earth, in order to 
constitute a metal. Lead, it has been observed, when 
melted in a strong fire, burns away like rotten wood ; all 
its properties as a metal are destroyed, and it is reduced 
to ashes. If you expose the ashes of lead to a strong 
fire, they will melt; but the melted substance will not 
be a metal , it will be a yellow or orange-coloured glass. 
If you pound the glass, and mix it with charcoal dust, or 
if you mix the ashes of the lead with charcoal dust, and 
expose either mixture to a melting heat, you will obtain, 
not a glass, but a metal , in weight, colour, consistency 
and every other property the same as lead. The ashes 
of lead melted without charcoal become glass ; the ashes 
of lead molted with charcoal become a metal. The char¬ 
coal, then, must have communicated something to the 
ashes of lead, by which they are changed from a glass to 
a metal. Charcoal consists of but two things—of ashes 
and of phlogiston; the ashes of charcoal, though united 
with the ashes of lead, would only produce glass; it 
must therefore be the other constituent part of charcoal, 
or phlogiston, which is communicated to the ashes of 
lead, and by an union with which the ashes are restored 
to their metallic form. The ashes of lead can never be re¬ 
stored to their metallic form without their being united 
with some matter containing phlogiston, and they may bo 
reduced to their metallic form by being united with ang 
substance containing phlogiston in a proper state, whe¬ 
ther that substance be derived from the animal, vegeta¬ 
ble, or mineral kingdom; and thence we conclude not 
only that phlogiston is a necessary part of a metal, but 
that phlogiston has an identity belonging to it, from 
whatever substance in nature it be extracted. And this 
assertion still becomes more general, if we may believe 
that metallic ashes have been reduced to their metallic 
form, both by the solar rays and the electrical fire.” 
The foregoing account by Dr. Watson is almost a 
translation from Stahl's ‘ Zymotechnica Fundamentals, 
simulque experimentum novum sulphur verum arte pro- 
ducendi,’ in which he establishes what may be called the 
permanency of chemical substance,—that metallic lead is 
reproducible from the ashes of lead, sulphur verum from 
the acid of sulphur. And, whether or not taking note 
of the oxidations and deoxidations effected, how little 
differently, even at the present day, would the actions 
referred to be described and explained! Is it not our 
habit to say that charcoal and sulphur and lead are 
bodies possessing potential chemical energy, that is 
phlogiston; that in the act of binning, their energy 
which was potential becomes kinetic or dynamical, and 
is dissipated in the form of light and heat; that the pro¬ 
ducts of their burning (including the gaseous product 
now known to be furnished by the burning of charcoal)^ 
are substances devoid of chemical energy, that is, of 
phlogiston; that when the acid substance furnished by 
burning sulphur is heated with charcoal, some energy ot 
the unburnt charcoal is transferred to the burnt sulphur, 
just as some energy of a raised weight may be transferred 
to a fallen one, whereby the burnt sulphur is unburnt, 
provided with energy, and enabled to burn again, and 
