« PreviousContinue »
to give a lucid, full, and satisfactory criticism on his voluminous publications. We shall, therefore make cursory observations on the nature and tendency of his works, elucidated by several extracts.
His first publication was an English Grammar upon an improved plan, for the use of his pupils at Nantwich. This elementary work is at present but little known.
Soon after his removal to Warrington Academy, in 1761, he published a Chart of Biography, which was favourably received by the public, as was also his Chart of History.
His department in language, & as professor of the belles-lettres, called forth his critical powers; and he published “A Course of Lectures on Oratory and Criticism.” In this work he displayed much erudition, and, as an admirer of the metaphysical philosophy of Hartley, he applied that philopher's theory of association to objects of taste, in a clear and satisfactory manmer. This production, however, would never have established his fame, nor is it of such general and practical utility as Blair's Lectures.
Natural Philosophy, which had ever been his favourite study, was the department of science in which this ingenious man was destined to shine. Electricity was the first branch of physics, which engaged his attention.
Accordingly, he wrote “The History of Electricity,” which was published at Warrington, in 1767, in one volume quarto. A circumstance which facilitated his success in this arduous undertaking, was his personal intercourse with the celebrated Dr. Franklin, and
This scientific history was read by men of taste, and passed through five editions. It is valuable not only for the facts recorded, respecting the rise and progress of the science, but also for several original experiments.
Encouraged by the success of this publication, the Doctor conceived the design of recording the rise and progress of the other sciences. Accordingly, his “History and Present State of Discoveries, relating to Vision, Light, and Colours,” was published in 1772, in 2 volumes, quarto. This work was not so favourably received as his History of Electricity; the subject had been handled by men of the first rate talents; and consequently had not that charm of novelty which rendered his account of electricity so amusing. The failure of this publication, induced our philosopher to relinquish his plan, and to turn his attention to a subject little known, though of the utmost importance. His “Experiments and Observations on different Kinds of Air,” immortalized his name, and placed him in the first rank of natural philosophers.
The first volume of this useful work was published in 1774, in octavo, and inscribed to his patron the Earl of Shelburne.
In the preface to the second edition, Dr. Priestley speaks of his researches with the candour and modesty of a philosopher, and with the humility of a pious man.
“I find it absolutely impossible,” says he, “ to produce a work on this subject that will be any thing like complete. My first publication I acknowledge to be very imperfect, and the present, I am as ready to acknowledge, is still more so. But, paradoxical as it may seem, this will ever be the case in natural science,
so long as the works of God are, like himself, infinite and inexhaustible. In compleating one discovery, we never fail to get an imperfect knowledge of others, of which we could have no idea before; so that we cannot solve one doubt without creating several new ones.”
The socond volume of this excellent work was puhlished in 1775, and dedicated to Sir John Pringle, Bart. President of the Royal Society; and the third volume, published in 1777, was inscribed to that noble patriot and philosopher, the Earl of Stanhope.
The results of several curious experiments are detailed in these volumes, by our philosopher, with candour, and several of his discoveries are of the utmost importance to mankind.
In the course of his numerous experiments, made with air infected by animal respiration, he discovered that it was restored to its common purity by vegetation. From which he makes the following just conclusion:
“Since the plants that I made use of mani
festly grow and thrive in putrid air; since
putrid air is well known to afford proper nouH
rishment for the roots of plants; and since it is likewise certain that they receive nourishment by their leaves, as well as by their roots, it seems to be exceedingly probable, that the putrid effluvium is in some measure extracted from the air, by means of the leaves of plants, and, therefore, that they render the remainder more fit for respiration.”
“That plants are capable of perfectly restoring air, injured by respiration, may, I think, be inferred with certainty from the perfect restoration, by this means, of air which had passed through my lungs, so that a candle would burn in it again, though it had extinguished flame before, and a part of the same original quantity of air still continued to do so.
“These proofs of a partial restoration of air, by plants in a state of vegetation, though in a confined and unnatural situation, cannot but render it highly probable, that the injury which is continually done to the atmosphere, by the respiration of such a number of animals, and
the putrefaction of such a masses of both vegetable and animal matter, is, in part at least,
repaired by the vegetable creation. And, notwithstanding the prodigious mass of air, that is corrupted daily by the above-mentioned causes;