In this situation I naturally resumed my application to speculative theology, which had occupied me at Needham, and which had been interrupted by the business of teaching at Nantwich and Warrington. By reading with care Dr. Lardner’s letter on the logos, I became what is called a Socinian soon after my settlement at Leeds; and after giving the closest attention to the subject, I have seen more and more reason to be satisfied with that opinion to this day, and likewise to be more impressed with the idea of its importance.
On reading Mr. Mann’s Dissertation on the times of the birth and death of Christ, I was convinced that he was right in his opinion of our Saviour’s ministry having continued little more than one year, and on this plan I drew out a Harmony of the gospels, the outline of which I first published in the Theological Repository, and afterwards separately and at large, both in Greek and English, with Notes, and an occasional Paraphrase. In the same work I published my Essay on the doctrine of Atonement, improved from the tract published by Dr. Lardner, and also my animadversions on the reasoning of the apostle Paul.
The plan of this Repository occurred to me on seeing some notes that Mr. Turner of Wakefield had drawn up on several passages of scripture, which I was concerned to think should be lost. He very much approved of my proposal of an occasional publication, for the purpose of preserving such original observations as could otherwise probably never see the light. Of this work I published three volumes while I was at Leeds, and he never failed to give me an article for every number of which they were composed.
Giving particular attention to the duties of my office, I wrote several tracts for the use of my congregation, as two Catechisms, an Address to masters of families on the subject of family prayer, a discourse on the Lord’s Supper, and on Church discipline, and Institutes of Natural and Revealed religion. Here I formed three classes of Catechumens, and took great pleasure in instructing them in the principles of religion. In this respect I hope my example has been of use in other congregations.
The first of my controversial treatises was written here in reply to some angry remarks on my discourse on the Lord’s Supper by Mr. Venn, a clergyman in the neighbourhood. I also wrote remarks on Dr. Balguy’s sermon on Church authority, and on some paragraphs in Judge Blackstone’s Commentaries relating to the dissenters. To the two former no reply was made; but to the last the judge replied in a small pamphlet; on which I addressed a letter to him in the St. James’s Chronicle. This controversy led me to print another pamphlet, entitled The Principles and Conduct of the Dissenters with respect to the civil and ecclesiastical constitution of this country. With the encouragement of Dr. Price and Dr. Kippis, I also wrote an Address to Protestant Dissenters as such; but without my name. Several of these pamphlets having been animadverted upon by an anonymous acquaintance, who thought I had laid too much stress on the principles of the Dissenters, I wrote a defence of my conduct in Letters addressed to him.
The methodists being very numerous in Leeds, and many of the lower sort of my own hearers listening to them, I wrote an Appeal to the serious professors of Christianity, an Illustration of particular texts, and republished the Trial of Elwall, all in the cheapest manner possible. Those small tracts had a great effect in establishing my hearers in liberal principles of religion, and in a short time had a far more extensive influence than I could have imagined. By this time more than thirty thousand copies of the Appeal have been dispersed.
Besides these theoretical and controversial pieces, I wrote while I was at Leeds my Essay on Government mentioned before, my English Grammar enlarged, a familiar introduction to the study of electricity, a treatise on perspective, and my Chart of History, and also some anonymous pieces in favour of civil liberty during the persecution of Mr. Wilkes, the principal of which was An Address to Dissenters on the subject of the difference with America, which I wrote at the request of Dr. Franklin, and Dr. Fothergil.
But nothing of a nature foreign to the duties of my profession engaged my attention while I was at Leeds so much as the prosecution of my experiments relating to electricity, and especially the doctrine of air. The last I was led into in consequence of inhabiting a house adjoining to a public brewery, where I at first amused myself with making experiments on the fixed air which I found ready made in the process of fermentation. When I removed from that house, I was under the necessity of making the fixed air for myself; and one experiment leading to another, as I have distinctly and faithfully noted in my various publications on the subject, I by degrees contrived a convenient apparatus for the purpose, but of the cheapest kind.
When I began these experiments I knew very little of chemistry, and had in a manner no idea on the subject before I attended a course of chemical lectures delivered in the academy at Warrington by Dr. Turner[10] of Liverpool. But I have often thought that upon the whole, this circumstance was no disadvantage to me; as in this situation I was led to devise an apparatus, and processes of my own, adapted to my peculiar views. Whereas, if I had been previously accustomed to the usual chemical processes, I should not have so easily thought of any other; and without new modes of operation I should hardly have discovered any thing materially new.[11]
[10] Dr. TURNER was a Physician at Liverpool: among his friends a professed Atheist. It was Dr. Turner who wrote the reply to Dr. Priestley’s letters to a philosophical unbeliever under the feigned name of Hammon. He was in his day a good practical chemist. I believe it was Dr. Turner who first invented, or at least brought to tolerable perfection, the art of copying prints upon glass, by striking off impressions with a coloured solution of silver and fixing them on the glass by baking on an iron plate in a heat sufficient to incorporate the solution with the glass. Some of them are very neatly performed, producing transparent copies in a bright yellow upon the clear glass.