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Robert Boyle, The Sceptical Chymist (1661)

Read the full text of the 1911 Everyman edition online at the Internet Archive or at Forgotten Books.

Useful explanatory annotations to the 1911 edition can be found here.


(if you don’t want to tackle the whole)

Robert Boyle
The Sceptical Chymist
(1911 Everyman edition)



…I observe, that of late chymistry begins, as indeed it deserves, to be cultivated by learned men who before despised it; and to be pretended to by many who never cultivated it, that they may be thought not to be ignorant of it: whence it is come to pass, that divers chymical notions about matters philosophical are taken for granted and employed, and so adopted by very eminent writers both naturalists and physicians. Now this I fear may prove somewhat prejudicial to the advancement of solid philosophy: for though I am a great lover of chymical experiments, and though I have no mean esteem of divers chymical remedies, yet I distinguish these from their notions about the causes of things and their manner of generation….

…I hope also it will not be unacceptable…to find here together, besides several experiments of my own purposely made to illustrate the doctrine of the elements, divers others scarce to be met with, otherwise then scattered among many chymical books: and to find these associated experiments so delivered as that an ordinary reader, if he be but acquainted with the usual chymical terms, may easily enough understand them; and even a wary one may safely rely on them. These things I add, because a person anything versed in the writings of chymists cannot but discern by their obscure, ambiguous, and almost enigmatical way of expressing what they pretend to teach, that they have no mind to be understood at all, but by the sons of Art (as they call them), nor to be understood even by these without difficulty and hazardous trials….And as the obscurity of what some writers deliver makes it very difficult to be understood; so the unfaithfulness of too many others makes it unfit to be relied upon. For though unwillingly, yet I must for the truth sake, and the reader’s, warn him not to be forward to believe chymical experiments when they are set down only bv way of prescriptions, and not of relations; that is, unless he that delivers them mentions his doing it upon his own particular knowledge, or upon the relation of some credible person, avowing it upon his own experience.

For I am troubled, I must complain, that even eminent writers, both physitians and philosophers, whom I can easily name, if it be required, have of late suffered themselves to be so far imposed upon, as to publish and build upon chymical experiments, which questionless they never tried; for if they had, they would, as well as I, have found them not to be true. And indeed it were to be wished, that now that those begin to quote chymical experiments that are not themselves acquainted with chymical operations, men would leave off that indefinite way of vouching the chymists say this, or the chymists affirm that, and would rather for each experiment the alleged name the author or authors upon whose credit they relate it; for, by this means they would secure themselves from the suspicion of falsehood (to which the other practice exposes them), and they would leave the reader to judge of what is fit for him to believe of what is delivered, whilst they employ not their own great names to countenance doubtful relations; and they will also do justice to the inventors or publishers of the true experiments, as well as upon the obtruders of false ones. Whereas by that general way of quoting the chymists, the candid writer is defrauded of the particular praise, and the impostor escapes the personal disgrace that is due to him….




…It was on one of the fairest days of this summer that the inquisitive Eleutherius came to invite me to make a visit with him to his friend Carneades. I readily consented to this motion…[and] accompanied him to the lodging of Carneades, where when we were come, we were told by the servants that he was retired with a couple of friends (whose names they also told us) to one of the arbours in his garden, to enjoy under its cool shades a delightful protection from the yet troublesome heat of the sun.

…[W]e found Carneades, Philoponus, and Themistius, sitting close about a little round table, on which, besides paper, pen, and ink, there lay two or three open books ; Carneades appeared not at all troubled at this surprise, but rising from the table, received his friend with open looks and arms, and welcoming me also with his wonted freedom and civility, invited us to rest ourselves by him…

Carneades [began], “Notwithstanding the subtile reasonings I have met with in the books of the peripatetics, and the pretty experiments that have been shewed me in the laboratories of chymists, I am of so diffident or dull a nature, as to think that if neither of them can bring more cogent arguments to evince the truth of their assertion than are wont to be brought, a man may rationally enough retain some doubts concerning the very number of those material ingredients of mixt bodies, which some would have us call elements, and others principles….[W]hen I took the pains impartially to examine the bodies themselves that are said to result from the blended elements, and to torture them into a confession of their constituent principles, I was quickly induced to think that the number of the elements has been contended about by philosophers with more earnestness than success. This unsatisfiedness of mine has been much wondered at by these two gentlemen” (at which words he pointed at Themistius and Philoponus), “who though they differ almost as much betwixt themselves about the question we are to consider, as I do from either of them, yet they both agree very well in this, that there is a determinate number of such ingredients…[it] is wont to be clearly enough demonstrated both by reason and experience. This has occasioned our present conference….”

Eleutherius…then address[ed] his speech to Carneades, “I esteem it no small happiness that I am come here so luckily this evening. For I have been long disquieted with doubts concerning this very subject which you are now ready to debate….and I am not a little pleased to find that you are resolved on this occasion to insist rather on experiments than syllogisms. For I, and no doubt you, have long observed, that those dialectical subtleties, that the schoolmen too often employ about physiological mysteries, are wont much more to declare the wit of him that uses them, than increase the knowledge or remove the doubts of sober lovers of truth. And such captious subtleties do indeed often puzzle and sometimes silence men, but rarely satisfy them. Being like the tricks of jugglers, whereby  men doubt not but they are cheated, though oftentimes they cannot declare by what flights they are imposed on.  And therefore I think you have done very wisely to make it your business to consider the phenomena relating to the present question, which have been afforded by experiments, especially since it might seem injurious to our senses, by whose mediation we acquire so much of the knowledge we have of things corporal, to have recourse to far-fetched and abstracted ratiocinations, to know what are the sensible ingredients of those sensible things that we daily see and handle, and are supposed to have the liberty to untwist (if I may so speak) into the primitive bodies they consist of.”

…[U]pon the same account”  (he added), “we agreed to discourse of the opinions to be debated, as we have found them maintained by the generality of the assertors of the four elements of the one party, and of those that receive the three principles on the other, without tying ourselves to enquire scrupulously what notion either Aristotle or Paracelsus, or this or that interpreter or follower of either of those great persons, framed of elements or principles; our design being to examine, not what these or those writers thought or taught, but what we find to be the obvious and most general opinion of those who are willing to be accounted favorers of the peripatetic or chymical doctrine concerning this subject.”

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