Three examples of Cullen's diagrams of single elective affinity reactions (middle), with the crochet ‘{’ representing the bonded association or union, and the dart ‘→’ representing the affinity. The modern equivalent reaction equation is shown to the right of each affinity reaction. [3] |
“Chemistry is an art that has furnished the world with a great number of useful facts, and has thereby contributed to the improvement of many arts; but these facts lie scattered in many different books, involved in obscure terms, mixed with many falsehoods, and joined to a great deal of false philosophy; so that it is no great wonder that chemistry has not been so much studied as might have been expected with regard to so useful a branch of knowledge, and that many professors are themselves but very superficially acquainted with it. But it was particularly to be expected, that, since it has been taught in universities, the difficulties in this study should have been in some measure removed, that the art should have been put into form, and a system of it attempted—the scattered facts collected and arranged in a proper order. But this has not yet been done; chemistry has not yet been taught but upon a very narrow plan. The teachers of it have still confined themselves to the purposes of pharmacy and medicine, and that comprehends a small branch of chemistry; and even that, by being a single branch, could not by itself be tolerably explained. I do not choose the invidious task of derogating from established reputations; but were it necessary, I could easily show that the most celebrated attempts towards a system or course of chemistry are extremely incomplete, as examining but a few of the objects of chemistry; that of those examined a very scanty and imperfect account of their relations to other bodies is given ; and that, even what is given, is in a method inconvenient and faulty. Now this is the case with the generality of the books on chemistry; but I must take notice, however, that Dr Stahl is one who has endeavored to avoid these faults; he has taught chemistry with a more general view, and attempted to collect the chemical facts, and to range them in a better order. Perhaps we have the substance of Dr Stahl's lessons, in a book published by a disciple of his, Dr Juncker of Halle, under the title of Conspectus Chemiae. This is the fullest collection that I have met with, and I have made a good deal of use of it, and you may do so too; but I must notice at the same time, that it is written in such a clumsy manner, is mixed with so much pedantic, trifling philosophy, and is often so inaccurate and superficial in describing experiments, that it will not contribute much to the propagating of chemical knowledge.”— William Cullen (c.1748), “Fragment of Early Chemistry Lecture” [5]
“After Boerhaave's decease, the lectures on chemistry were continued at Leyden by his pupil Gaubius, whose lectures on that subject seem to have been circulated extensively in manuscript, and to have been much sought after by Cullen.”— John Thomson (1832), An Account of the Life, Lectures and Writings of William Cullen, Volume One (pg. 38) [5]