HEADS OF LECTURES

ON A COURSE OF

EXPERIMENTAL PHILOSOPHY,

PARTICULARLY INCLUDING

CHEMISTRY,

DELIVERED AT THE NEW COLLEGE IN HACKNEY.

By JOSEPH PRIESTLEY, LL.D. F.R.S.

AC. IMP. PETROP. R. PARIS. HOLM. TAURIN. AUREL. MED.
PARIS. HARLEM. CANTAB. AMERIC. ET PHILAD. SOC.

QUI DOCET DISCIT.—WM. LILLY

LONDON:

PRINTED FOR J. JOHNSON, NO. 72, ST. PAUL'S CHURCH-YARD.

1794.

THE PREFACE.

Situated, as I happily am, in the neighbourhood of the New College at Hackney, an institution that does honour to the Dissenters, an institution open to all persons without distinction[1], and connected as I am by friendship with the tutors, I was glad to give it every assistance in my power; and therefore undertook to read the Lectures on History and General Policy which I had composed when I was tutor at Warrington, and also to give another course on the subject of Experimental Philosophy. With this view I drew up the following Heads of Lectures; and, to save the students the trouble of transcribing them, they are now printed. To other persons they may serve as a compendious view of the most important discoveries relating to the subject.

As it was found most convenient, with respect to the other business of the college, to confine this course to one lecture in a week, I contrived to bring within that compass as much of the subject of experimental philosophy as I well could, and especially to include the whole of what is called chemistry, to which so much attention is now given, and which presents so many new fields of philosophical investigation.

Besides that the plan of the young gentlemen's studies would not admit of it, I think it most advisable not to trouble beginners with more than a large outline of any branch of science. By this means they are not fatigued by too long an attention to any one subject, a greater variety of articles may be brought before them, and in future life they may pursue any of them as much farther as their inclination may dispose, and their ability and opportunity shall enable, them to do it.

I do not give any account of the experiments introduced into the several lectures. They will be sufficiently indicated by the subjects of them. They were as many as I could conveniently make within the time; and where the experiments themselves could not be made, I usually exhibited both the different substances employed in them, and those that were the result of them.

As these lectures were calculated for the use of the students at the New College, I prefix an Address to them, the same in substance with that which I delivered to them at the close of the session of 1791. In it may be seen a specimen of the language we hold to them on the subject of politics, which with reasonable men will serve as an answer to the many calumnies that have been thrown out against us, as disaffected to the government of this country.

Such institutions will, indeed, always be objects of hatred and dread to bigots and the advocates for arbitrary power, but the pride of a truly free country. I therefore conclude with my earnest prayer (the accomplishment of which the present state of the College does not allow us to doubt) Esto perpetua.

THE DEDICATION.

TO THE STUDENTS AT THE NEW COLLEGE IN HACKNEY.

My young Friends,

Having drawn up the following Heads of Lectures for your use, I take the liberty thus publickly to dedicate them to you; and as I earnestly wish for your improvement and happiness in all respects, excuse me if I take the farther liberty of making a few observations, and giving you some advice, of a more general nature, adapted to your age and circumstances.

As you will soon leave this place of education, and enter upon your several professions and employments, I hope your conduct will demonstrate to the world the solid advantages of this institution, and that the great expence attending it, and the best attention of the managers, have not been bestowed in vain.

Many liberal friends of science, of virtue, and of religion, have contributed to procure you the advantages which you enjoy. They have spared no pains to provide able and careful tutors, and you have had every other advantage for the prosecution of your studies that they could procure you, unclogged by any subscription to articles of faith, or obligation of any other kind, besides such as they have deemed necessary for your own good, and to give the institution its greatest effect. This is an advantage you could not have found elsewhere, at least in this country. And in every seminary of education much more depends upon opportunity for study, free from any obstruction, and undue bias, than upon the ability of tutors; though there is an additional advantage when they are able men, and eminent in the branches of science which they undertake to teach. But this is by no means so essential as many other circumstances.

Whatever be the qualifications of your tutors, your improvement must chiefly depend upon yourselves. They cannot think or labour for you. They can only put you in the best way of thinking and labouring for yourselves. If, therefore, you get knowledge, you must acquire it by your own industry. You must form all conclusions, and all maxims, for yourselves, from premises and data collected, and considered by yourselves. And it is the great object of this institution to remove every bias the mind can lie under, and give the greatest scope to true freedom of thinking and inquiry. And provided you be intelligent and virtuous men, and good citizens, it will be no cause of regret to the friends of this institution, if, with respect to religion, or politics, you adopt systems of principles, and maxims of conduct, very different from theirs.

Give me leave, now that I am addressing you as young men, and young students, to suggest a caution on a subject, of the importance of which it is hardly possible that you should be sufficiently aware, because it is only impressed by that experience which you have not yet had. I mean that degree of vanity which generally accompanies the acquirements that diligent persons of your age make in places of liberal education, and the contempt they are too apt to entertain for those who have not made the same proficiency with themselves. And I assure you, that in the observations I shall make on this subject, I have no view whatever to any thing that I have observed, or heard, of any of you in particular. But I have been in your situation myself, and I know the importance of these observations to students in general.

You are now at an age in which young persons usually make the most sensible advances in knowledge, and in which the understanding appears to ripen the most rapid manner. You are able to say every year, every month, and almost every