conviction founded on the best evidence, that the nature of the subject admits. In fine, it places the mind in the happy medium between credulity, and scepticism, the two extremes of human weakness and human presumption. Bigotry and scepticism can scarcely find admittance to the heart of a mathematician. To doubt of truth was not the property of Pythagoras, Plato, Bacon, Boyle, Huygens, Euler, Maclaurin, or Newton, but of the unmathematical Epicurus, Lucretius, Herbert, Spinosa, Voltaire, Hume, and Gibbon.

As every pursuit, to which a man is more or less inclined, produces a correspondent effect upon his character, conduct, and sentiments; so there is no doubt, but as a mathematician Mr. Walker must have experienced the ennobling influence of that study, to which he was so much addicted. Perhaps therefore we may be excused for this digression, from it's intimate connexion with our present subject.

About this time Mr. Walker was applied

to

to by a gentleman of great respectability, to undertake the charge of his eldest son. This was his first entrance upon the business of education, and for this he was indebted to the strong recommendation of Dr. Priestley. With the Doctor he had for some time been intimately acquainted, and a frequent correspondence at this period subsisted between them. From some of the Doctor's letters it appears, that Mr. Walker had at his request furnished a few papers for the Royal Society, which were to have been inserted in their Memoirs; but the person to whose care they were intrusted having mislaid them, they could never afterwards be found. It was probably in consequence of these communications, that he was soon after elected one of their members. As no memorandums of these papers are existing, it is impossible to ascertain the subjects of them; but the following extracts from the Doctor's letters allude to them, and are here inserted, as affording a singular proof of f 2

the

the indefatigable activity and literary ardour of his mind.

"Your two quarto manuscripts, which you imagined you had left on the road, ' are safe at . I wish they were in your "possession, because I think they would be "of service to you, in drawing up a few 66 more papers for the Royal Society. I was "in hopes, that before this time I should "have received your communication for the

Repository.... I have been writing two "small controversial tracts, and a piece on "church discipline, which I was led to think "of from what you said to me on the sub

ject. I am afraid however you will not "like it. I have prepared for the press an "enlarged edition of my Essay on Govern"ment, and as soon as I shall have dispatched

a few more small articles, I shall sit down "in good earnest to the History of Experi"mental Philosophy, proposals for which I "have printed.... 18th of March, 1770.. "On Thursday next your papers will be pre

"sented

1

"sented to the Royal Society, but it be may "several weeks before they can be read..

"A friend of mine, to whom I communi"cated your query about the doctrine of "fluxions, writes to me from Paris, that "the mathematicians there know of no "treatise containing such a démonstration " as you mention but they tell him there "is a sketch of something of the kind in "the Encyclopédie. If you have no op

portunity of consulting it, I will do it for

you when I am in London. I wish how"ever you would send your papers to Dr. "Price, who will present them to the Society. "I do not return to Paris.. . . As you have not "studied Hartley, it would be to no purpose "to write to you about metaphysics. I be"lieve nothing of any original determina"tion of the mind to objects of morality, or

any other objects: and though you and "Mr. Hutchinson say there must be such things, I do not see a shadow of proof for "it. I do not expect however, that the reading of Hartley will convince you, any

"more than another reading of Hutchinson "would convince me. We are both too old, "to adopt a new general system of metaphy"sics.... I have lately been very successful "in the prosecution of my experiments on "air, and intend soon to draw up a supple"ment to my Treatise on that subject. I "have two more acid airs, the vitriolic and "the vegetable, and also a species of air σε got from red lead, and other substances, "that is near six times as good as common "air. This very remarkable fact I hope will "lead me much farther.... I am also about "to publish A Harmony of the Evangelists "in Greek and English, upon the plan of "that in the Repository. If you have any "thoughts on the subject, I shall thank "for the communication of them."

you

Mr. Walker's marriage at this particular period prevented his acceptance of a situation, which in other respects would have been highly desirable. The late Marquis of Lansdown had applied to Dr. Price, to recommend to him a gentleman of character

and