Whilst at Warrington he published a Chart of Biography, exhibiting by lines and spaces the succession of the eminent men in every age and of every profession, with the relative length of their lives, and in such manner that at any given epoch it could be seen not only who flourished in it, but how all their ages stood with respect to one another, who were a man’s contemporaries, how far any of them was before him, or how far after him, in the order of their births or deaths.
The Chart of Biography procured for its compiler the degree of Doctor of Laws of the University of Edinburgh.
It has been said of Priestley that he was not a man who made friends. If it is meant by this that he was essentially a self-centred recluse, who sought his relaxation in change of occupation, or only within his own family circle, the statement gives a wholly imperfect idea of the man and is very wide of the truth.
In reality he was one of the most gregarious and most easily approachable of individuals, a man of strong, active human sympathies and of much social charm. There is abundant evidence of this in the testimony of his contemporaries; it is illustrated by numberless anecdotes, and is reflected in almost every letter of his correspondence.
It was, doubtless, under the impulse of the social instincts of his nature that, whilst at Warrington, he was led to begin the practice of spending one month in every year in London. This, remarks his son, was of great use to him. He saw and heard a great deal. A new turn was frequently given to his ideas. New and useful acquaintances were formed, and old ones confirmed. London then, as now, was the centre of the intellectual life of the kingdom and the Royal Society the seat of its scientific activity. To a man of Priestley’s versatility and eagerness, whose curiosity ranged practically over every department of human knowledge, these annual visits were a sort of intellectual tonic and gave a powerful stimulus to his activity.
On the first of them he made the acquaintance of men who, in their several capacities, proved to be true and valuable friends, notably, Dr Richard Price, Mr Canton, and Dr Benjamin Franklin.
Dr Price, a philosopher, and an eminent nonconformist divine, and one of the leading Arians of his time, is best known by his work on morals, and by his writings on financial and political questions. Among these, his papers in the Philosophical Transactions on “Life Insurance” and on the “Proper Method of Calculating the Values of Contingent Reversions,” are specially noteworthy. His pamphlet on the National Debt is said to have influenced Pitt in establishing the Sinking Fund for its extinction, and that on the “Policy of the War with America” to have contributed to the declaration of independence by the Americans. His liberal opinions gained him the friendship and patronage of Lord Shelburne. The acquaintance with Priestley soon ripened into a lasting friendship, which was in nowise disturbed by the controversy on materialism and necessity in which they subsequently engaged. Price and Priestley held similar views as to the French Revolution, and both were denounced with equal fierceness by Burke. Price died in the spring of 1791, and his funeral sermon was preached by Priestley, who succeeded him in the care of the Gravel Pit Meeting at Hackney. He was a man for whom Priestley ever entertained the warmest feelings of friendship on the ground of his amiable simplicity, his truly Christian spirit, disinterested patriotism and true candour.
John Canton, a notable schoolmaster in his day, is best known for his electrical inquiries and for his work on the compressibility of water, and his name is associated with the phosphorescent substance first obtained by him by calcining oyster shells with flowers of sulphur.
Among the Canton papers in the possession of the Royal Society is a letter from Seddon to Canton introducing Priestley, in which the latter is described as the author of A Chart of Biography and of an Essay on Education, and in which the writer says of the bearer:—
“You will find him a benevolent, sensible man, with a considerable share of learning. Besides the studies which belong to his profession, he has a taste for Natural Philosophy which will not render him less agreeable to you.”