And yet, in spite of the unqualified censure with which they were received, and of the severe condemnation of them by their own author, we are disposed to agree with Dr. Davy that posterity will not suffer these essays to be wholly blotted out from the records of science. That the experimental part was for the most part radically bad, that the generalisation was hasty and presumptuous, and the reasoning imperfect, cannot be gainsaid. But, withal, the essays display some of Davy’s best and happiest characteristics. There is dignity of treatment and a sense of the nobility of the theme on which he is engaged; the literary quality is admirable; there is clearness of perception and perspicuity of statement; the facts as he knew them--or as he thought he knew them--are marshalled with ingenuity and with a logical precision worthy of his model and teacher Lavoisier; his style is sonorous and copious, even to redundancy--some of the periods indeed glow with all the fervour and richness of his Royal Institution lectures. However wild and visionary his speculations may seem, minds like those of Coleridge and Southey were not insensible to the intrinsic beauty of some of his ideas. His theory of respiration might not be true, but it had at least the merit of poetic charm in its consequence that the power and perspicacity of a thinker had some relation to the amount of light secreted by his brain. Even good old Dr. Priestley, whose Pegasus could never be stirred beyond the gentlest of ambles, tells us in the Appendix to his “Doctrine of Phlogiston Established” that Mr. H. Davy’s essays had impressed him with a high opinion of the philosophical acumen of their author. “His ideas were to me new and very striking; but,” he adds, with a caution that was not habitual, “they are of too great consequence to be decided upon hastily.” Among the letters entrusted to me is one from Priestley, which must have been particularly gratifying to the young man. It is as follows:-- “Northumberland, _Oct. 31, 1801_. “SIR,--I have read with admiration your excellent publications, and have received much instruction from them. It gives me peculiar satisfaction that, as I am far advanced in life, and cannot expect to do much more, I shall leave so able a fellow-labourer of my own country in the great fields of experimental philosophy. As old an experimenter as I am, I was near forty before I made any experiments on the subject of Air, and then without, in a manner, any previous knowledge of chemistry. This I picked up as I could, and as I found occasion for it, from books. I was also without apparatus, and laboured under many other disadvantages. But my unexpected success induced the friends of science to assist me, and then I wanted for nothing. I rejoice that you are so young a man; and perceiving the ardour with which you begin your career, I have no doubt of your success.