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John Freind at Oxford

Worth’s acquisition of John Friend’s seminal course of lectures at Oxford, Praelectiones chymicae, in quibus omnes fere operationes chymicae ad vera principia et ipsius naturae leges rediguntur, Oxonii habitae (Amsterdam, 1710) demonstrates not only his interest in chemical teaching at the University of Oxford, but also his commitment to a newtonian approach to science. Friend’s text was based on his series of lectures at Oxford and offers us an invaluable insight into chemical teaching and practice at the university in the early eighteenth century.

Despite the presence of Robert Boyle in Oxford in the 1650s there had been no official instruction in chemistry at the University of Oxford until the 1680s when Dr Robert Plot (1640-1696) was appointed as the first Professor of Chemistry. He was appointed in the same year, 1683, as the opening of the chemical laboratory included in Elias Ashmole’s planned museum, which later became known as the Ashmolean Museum. This momentum was not to last: following Plot’s resignation in 1689 there was no incumbent in the post until the election of John Friend (1675-1728) as Professor of Chemistry in 1704.


John Friend, Praelectiones chymicae… (Amsterdam, 1710), titlepage.

Friend’s mechanistic approach is amply demonstrated in his opening preface:

‘I have said but very little relating to the Principles, which are commonly mention’d in Books of Chymistry, because I thought it not worth while to confute Errors. These Treatises, I found, contain’d many things not only Trifling, and without any Foundation, but directly contrary to Experience. Therefore I chose rather to deduce this Mechanical Explication from the Experiments themselves, than as the way is with most Writers in this kind, to accommodate Experiments to some preconceiv’d Hypothesis.

For what is said concerning Attraction, the Force of which is very extensive in this Enquiry, is not bare Speculation, but taken from the very Nature of Things, and the Propension of Bodies, which they are observ’d to have one to another, especially that which Chymical Experiments discover to us.

As therefore I have advanc’d Reasonings, hitherto not understood by Chymical Writers, or at least not made use of by them, so I have sometimes from Experience given a Description of the Things themselves, very different from what we find in them. In which Undertaking, if I should not please those who are bigotted to some particular Sect, and who take for Principles uncertain Notions of Things, which no where exist; yet I hope so far to gain the good Esteem of such, who will not suffer their Judgments to be impos’d upon, as to be look’d on as one who has enter’d upon the true way of promoting this Study…’*

He outlined his method in his first lecture:

‘The Method therefore we shall take, will be, First, To explain the particular Operations, in that Natural Order they are connected one with another; and to shew at the same time by what Mechanical Force they are principally produced, and to what Uses they chiefly serve. Secondly, To declare the various Ways, in which ‘tis possible and usual for them to be perform’d. Thirdly, To relate the particular Experiments in their proper places, and to reduce them to the general Theory.’

As his 9 point plan makes clear, he was keen to present chemistry in a new, geometrical, light:

  1.  ‘All similar Bodies are in a Triplicate Ratio of their Homologous sides, and therefore Spheres are in a Triplicate Ratio of their Diameters, or are as the Cubes of their Diameters. Also in Similar bodies that are of the same Density, their Weights are as the Cubes of their Diameters: But their Superficies are in a Duplicate Ratio of their Diameters, or as the Square of their Diameters.
  2.  The Moments of Bodies, or the Quantities of Motion, are in a Ratio compounded of the quantity of Matter, and their Celerity.
  3.  If a Body be specifically heavier than the Fluid, into which it is immers’d, it descends with the Force, which answers to the excess of its Gravity: But if it be lighter than the Fluid, it is carried upwards by the Force, with which its own Gravity is exceeded by the Gravity of the Fluid.
  4.  That there is an Attractive Force, or that all the Parts of Matter are drawn towards one another.
  5. This Force is diffus’d but a very little way; so that when Bodies come to be at some distance, it almost vanishes. Nor does it come to be sensible, unless when the Particles of Matter draw nearer one to the other; But at the point of Contact it is strongest. And therefore the Attractive Force decreases in a Ratio of the increasing Distances, which is most than Duplicate.
  6.  This Force is different according to the various Texture and Density of the Particles: But in Gravity ‘tis quite otherwise, for that always remains the same, however the Texture of Bodies is chang’d.
  7. But the Attractive Force is greater in one side of the same Particle, than in an other.
  8. 8. Particles, by how much minuter they are, with so much the greater Velocity they approach each other. For the Attractive Force exerts it self only in those Particles which are very near one another; as for instance, in d and c; The Force of such as are remote is next to nothing. Therefore no greater Force is requir’d to move the Bodies ‘A’ and ‘B’, than what would put into motion the Particles ‘d’ and ‘c’, when disengag’d from the rest. But the Velocities of Bodies moving with the same Force are reciprocally, as the Bodies themselves. Therefore the more the Body ‘A’ exceeds the Particle ‘d’ in Magnitude, the less is its Velocity; and this Motion is so languid, that oftentimes ‘tis overcome by the Circumambient Medium, and other Bodies. Hence it is that this Attractive Force does scarce exert it self, unless in the smallest Particles, separated from the rest.
  9.  The Force by which Particles cohere among themselves arises from Attraction, and is chang’d many ways, according to the various quantity of Contact.’

Freind was keen in his first lecture to identify the right and wrong methods of chymistry: the continuing adherence in some quarters to the tria prima of Paracelsus was castigated, as were the popular chymistry courses on offer (though Freind does not name his targets). Equally he professed himself perplexed by the terms ‘Acid and Alkali, Words which are now in every Body’s Mouth’, urging his readers towards caution in their too-ready acceptance of them as explanatory terms in chemistry

Freind’s own text, initially printed at London in 1709, received popular acclaim – evident in the decision to publish it in the Netherlands. From there, as the translator of the 1712 English edition relates, it became known to the ‘Lipsick Acts’, the Acta Eruditorum printed at Leipzig, a journal which Worth also assiduously collected. It was this development that led Freind to printing not only an English 1712 edition but one which included his remarks on the scholarly comment emanating from Leipzig.

Freind was, on occasion, ready to give qualified praise: in his view Robert Boyle had ‘not so much laid a new foundation of Chymistry, as he has thrown down the old; he has left us plentiful Matter, from whence we may draw out a true Explication of things, but the Explication it self he has but very sparingly touch’d upon.’ Undoubtedly the most striking of the ‘plentiful matter’ left by Boyle was his famous experiment of the air pump, an improved version being illustrated in Worth’s copy of the 1725 collected works of Boyle:

Boyle’s air pump improved.
Robert Boyle, The philosophical works (London, 1725), 3 vols, vol 2, plate VIII.

For Boyle’s explanation of this see Experiments on Air.


*All texts from Freind are taken from the 1712 English translation: Chymical Lectures (London, 1712).

Debus, Allen G. (1986), ‘Chemistry and the Universities in the Seventeenth Century’, Academiae Analecta: Klasse der Wetenschappen, 48, 15-33 (30-31).

Debus, Allen G. (2001), Chemistry and Medical Debate: Van Helmont to Boerhaave (Science History Publications).

Guerrini, Anita (2004), ‘Freind, John (1675–1728), physician’, in Oxford Dictionary of National Biography.

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