AN ESSAY
ON
COMBUSTION,
WITH A VIEW TO
A NEW ART
OF
DYING AND PAINTING.
WHEREIN THE PHLOGISTIC AND ANTIPHLOGISTIC
HYPOTHESES ARE PROVED
ERRONEOUS.

BY MRS. FULHAME.

THE FIRST AMERICAN EDITION.

PHILADELPHIA.
PRINTED AND SOLD BY JAMES HUMPHREYS, <—- what a boss
Corner of Second and Walnut-streets, get these nuts!
1810.

ADVERTISEMENT

BY THE AMERICAN EDITOR.

THE interesting contents of the subsequent pages, by the very ingenious Mrs. Fulhame, are assuredly deserving of more attention, than they have hitherto received; for although published so far back as the year 1794, little notice has been paid to the numerous experiments, by which she has opposed the doctrines of combustion, &c. advanced by the respective advocates of the phlogistic and antiphlogistic theories. How successfully she has executed this, must be left to the candid inquirer after truth, who, provided the end be attained, does not stop to consider from what source it is derived.

Whether it be that the pride of science, revolted at the idea of being taught by a female, I know not; but assuredly, the accomplished author of this essay, has sufficiently evinced the adequacy of her acquirements, in the promulgation of opinions subversive of a part of the highly esteemed edifice, raised by the efforts of Lavoisier and others.

That the work has hitherto remained unknown in this favoured land, where freedom of inquiry is so sedulously cherished, is matter of surprise; especially when it is known that many years past, the author was elected an honorary member of the then-existing chemical society of Philadelphia, a distinction founded on the merit of this work; yet the doctrines here advanced, appear to have been known to but few individuals, for they have never been comprised in the lectures on chemistry, which are given in various parts of the Union – nor, till lately, has the work been adverted to, in any of the numerous volumes on the science which annually appear from the British press. Truth however, at length appears likely to dissipate those mists, which, from whatever cause arising, have hitherto opposed the merited estimation of the author: in some of the late English treatises, this lady is respectfully mentioned; more particularly by the learned Dr. Thompson, in the third edition of his invalu- able System of Chemistry,1 when speaking of the reduction of the muriate of gold, whilst liquid, by some of the combustibles, but which decomposition does not happen when dry; he adds "for these very interesting facts we are indebted to the ingenious Mrs. Fulhame:" he then proceeds to mention some of her experiments, and continues "Mrs. Fulhame ascertained, that this reduction of the gold does not happen in any case unless the salt be moistened with water: when perfectly dry, it is not altered. This is not peculiar to the action of combustibles on metallic salts: it holds also, as we shall see afterwards, with respect to the metals. But it is by no means easy to see what makes water so indispensably necessary. It is not, as is commonly supposed, in order to secure the fluidity of the mixture: for Mrs. Fulhame has shewn that ether, though a liquid, has no effect in reducing gold unless water be present. She accounts very ingeniously for the phenomena, by supposing that the water is decomposed. The combustible combines with its oxygen, while its hydrogen combines with the oxygen of the gold, and reproduces water. This theory accounts very well for the phenomena; but it would require some direct proof to establish it completely."

The concession admitted in the last sentence, from so celebrated a chemist as Dr. Thompson undoubted- ly is, although in some degree counteracted by the concluding paragraph, cannot but be esteemed a strong proof of the merit of the opinions here advanced; and as a tacit avowal, of the inadequacy of the usually received explanation, in accounting for the phenomena under consideration.

Convinced by the forcible arguments and experiments of the decomposition of water being essential in all the processes here detailed, and considering the subject much simplified by the exposition given; I cannot but think the same reasoning would apply in many other cases, where some of the most active and energetic agents, are, by the present explanation, altogether thrown into the back ground. Thus, in procuring nitrogen gas from muscular flesh by means of diluted nitric acid, we are told, "that the nitric acid does not furnish the nitrogen gas is obvious, from its saturating after its action as large a quantity of alkali as before; consequently it could not have suffered any decomposition."2 That this deduction is not in the true spirit of chemical philosophy, which looks to the action of affinity, by which decomposition, and recomposition may at the same time progress, I have little hesitation in saying; and that the case adverted to is a compound, and not a simple play of affinity must be allowed, or we entirely destroy the agency of the most powerful body united, whose presence is nevertheless admitted to be essential to the process. If we suppose the nitrogen to be expelled from the flesh, by the action of the acid, which, with the water is also decomposed, we shall have a double portion of oxygen and nitrogen, which may thus combine. The oxygen of the water uniting to the nitrogen of the flesh, will produce a fresh supply of nitric acid, and whilst the nitrogen of the original acid escapes, its oxygen will unite to the liberated hydrogen of the decomposed water, to form an equal quantity. At the conclusion of this process of double affinity then, we shall have a quantity of new formed acid and water equal to the original, but in which the original elements, have changed situations. By this explanation, the acid retains the place of activity it ought to hold; and the necessity of its presence, is hereby maintained.

In like manner it has been said that sulphuric acid is not decomposed in aiding the decomposition of water with iron in procuring hydrogen gas, because it saturates as much alkali as before; but the same objections may be made to the validity of this opinion as to the former; and the process may be more reasonably explained on the principles of compound affinity. When the water is decomposed, its hydrogen escapes, but the acid is also decomposed, and whilst the oxygen of the acid oxydates the iron, the oxy- gen of the water unites with the sulphur to form a similar quantity of acid, which dissolves the oxydated iron. It would seem incredible, that in any other way, either the nitric or sulphuric acids, should be essential to the processes adverted to; and from these and other circumstances, such as, that a metal placed in dry oxygen gas does not oxydize, which ought to result, if simple affinity only was requisite; and by observing in all the late ingenious experiments of Mr. Davy, the presence of moisture appears to be essential in the decomposition of the alkalies, &c. although he mentions it, as only rendering them conductors, I cannot doubt the justice of the opinions deduced by Mrs. Fulhame from her numerous and well conducted experiments: and although it may be grating to many, to suppose a female capable of successfully opposing the opinions of some of our fathers in science; yet reflection will serve to satisfy the mind devoted to truth, that she has certainly thrown a stumbling block of no small magnitude, in the way of sentiments we have been taught to consider as sacred.

PHILADELPHIA,

February 14th, 1810.