ments by which he was conducted to some most important results that were announced in his Bakerian lecture* for 1806.

We cannot here delay to give a detailed account of this highly interesting lecture, but can only remark that the views he promulgated were novel in the highest degree, and considered so important that the Institute of France awarded to him the prize founded by Napoleon for the most important discoveries in galvanism; and this too at a period when the national animosities existing between that country and England were in the highest degree excited.

"This grand display of scientific light," says Dr. Paris, "burst upon Europe like a splendid meteor, throwing its radiance into the deepest recesses, and opening to the view of the philosopher new and unexpected regions."—Vol. i, p. 227.

Encouraged by his unexampled success, and guided by the new principles which he had himself developed, he now "struck at once into. new paths of discovery;" and every successive announcement of his for years was hailed with enthusiastic admiration by the cultivators of science throughout the world and generally the public expectation, though highly raised, was admirably met. But it would be attributing to him something more than human, to say that every effort was equally successful.

Previous to this time, the alkalies potassa and soda, and the earths baryta, strontia, lime, magnesia, &c., had universally been considered simple substances, as they had resisted all attempts made to decompose them; or if any had made any conjectures concerning their composition, they certainly were nothing more than conjectures.

Davy himself had often speculated with regard to them; but in September, 1807, he commenced a series of experiments which terminated in the decomposition of potassa, and the demonstration of its true composition on the 19th of October following, an achievement which alone would have rendered his name immortal. This was effected by means of the new agent of decomposition, galvanic

This is a lecture given annually by a Fellow of the Royal Society, on some subject connected with natural history or experimental philosophy, in accordance with the will of a Mr. Baker, who died in 1774, and left by his will one hundred pounds to be invested, and the income of it paid each year to the person who should be selected for this purpose, by the president and council of the society. Davy delivered the lecture for the years 1806-10, and 1826.

electricity, three different batteries having been combined in one for this purpose. He showed conclusively that potassa is composed of a metal and oxygen which have so strong an affinity for each other that they can be separated only with the utmost difficulty. The new metal, though possessing unquestionable claims to be considered as such, he found to possess some very peculiar properties. It is quite soft, is lighter than water, oxydizes rapidly in the open air, and takes fire instantly when thrown upon water! We are informed by his relative, Mr. E. Davy, who was present, that when he first saw the minute globules of the new metal make their appearance, and take fire as they entered the atmosphere, "he could not contain his joy, but actually danced about the room in ecstatic delight; and some little time was required for him to compose himself sufficiently to continue the experiment.”

Soon after this he decomposed soda in the same manner. The new metals thus obtained, he proposed to call potassium and sodium, and the names have been universally adopted. Subsequently Davy applied this new engine to the decomposition of the alkaline earths baryta, strontia, lime, and magnesia, obtaining from them evident traces of their metallic bases, to which he gave the names barium, strontium, calcium, and magnesium. His attacks, however, upon the earths proper were less successful, though he was able to satisfy himself of the fact of their composition being altogether analogous to that of the other bodies of the same class. Subsequent discoveries have proved the perfect correctness of his views. His discovery of the composition of the fixed alkalies was announced in his second Bakerian lecture for the year 1807, and probably produced a greater sensation in the scientific world, than any similar announcement that was ever made. Its importance alone would have been sufficient to attract general attention; but the various circumstances connected with it, all tended to give it an extraordinary degree of interest, and increase the enthusiasm with which it was received.

As a matter of course, the experiments of Davy were immediately repeated by others, and with similar results; but all did not at once acquiesce in his views with regard to the real composition of the alkalies. We will not, however, here enter into a detailed account of the short controversy that ensued. It is sufficient that numerous minute investigations which have since been made, have

fully established the truth of Davy's conclusion, viz., that potassa is simply a protoxyd of its metallic base, potassium.

Soon after the delivery of his second Bakerian lecture, early in Nov., 1807, which we have already mentioned, he was thrown into a severe fit of illness, which continued many weeks, and which his physicians affirmed was occasioned by his continued toil and excitement during several months preceding. It ought to be mentioned also, as Dr. Paris has done, that he was at this time extremely irregular and even intemperate in some of his habits, against which men of sedentary life ought always especially to guard.

Davy's illness was long and severe, but he eventually recovered without permanent injury to his constitution. The regular annual course of chimical lectures in the institution was given during his illness by another person. Soon after his recovery he started the project of constructing a magnificent galvanic battery for the Royal Institution by private subscription, which, by the munificence of a few individuals was shortly accomplished. This splendid piece of apparatus, it is believed, was the largest instrument of the kind ever constructed. "It consisted of two hundred instruments, connected together in regular order, each composed of ten double plates arranged in cells of porcelain, and containing in each plate thirty-two square inches, so that the whole number of plates is two thousand, and the whole surface 128,000 square inches."*

With this battery he performed many magnificent experiments; but it is found that little is gained by increasing the size of such instruments beyond even quite narrow limits. The results therefore were by no means such as were generally expected. For several years succeeding this period, Davy labored incessantly in the laboratory of the Royal Institution, and did much, by his failures as well as by his discoveries, to settle many of the truths of science. Self-confident even to a fault, he seems to have pursued his investigations with a perfect indifference, not to say contempt, for the opinions of others, which were often alluded to in terms not the most respectful. With a quickness of perception perhaps scarcely ever equalled, he sometimes adopted his conclusions quite too hastily; and, crude and erroneous as they were, published them at once to the world. In candor, however, it must be confessed that he was always ready to retract when convinced of mistake; and in some * Davy's Elements of Chimical Philosophy, page 85. Am. edition.

instances, as Dr. P. justly remarks, he displayed great vigor in disentangling himself from the webs of error which he had previously fabricated. That he always escaped a sneer cannot be affirmed of him, but his very great services to the cause of science, and his acknowledged great abilities, saved him from the otherwise certain consequences of his rash course.

About this time he became engaged in a most acute controversy concerning the nature of oxymuriatic acid, as it was then called, with the late distinguished Dr. Murray of Edinburgh. Davy had some time before adopted and published some peculiar opinions concerning the nature of this substance, and its near relative, muriatic [hydrochloric] acid, but subsequently withdrew them, and announced the important fact-for such it has been proved-that oxymuriatic acid, which had been considered a compound of muriatic acid and oxygen, as the name implies, is a simple substance; and that muriatic [hydrochloric] acid is a compound of this substance and hydrogen. To the simple substance he gave the name chlorine, in allusion to its yellowish green color, a name which has since been universally adopted. He showed that it could not be decomposed by any means then known, and that it was analogous in many of its properties and relations to oxygen, with which it should be classed.

Dr. Murray, on the publication of these views by Davy, took decided ground against them; and nearly all the leading scientific men of Europe probably strongly sympathized with him.

"Opinions more unexpected," says Dr. M., at the commencement of the controversy, "have seldom been announced to chimists, than those lately advanced by Mr. Davy with regard to the constitution of the muriatic and oxymuriatic acids; viz., that the latter is not a compound of muriatic acid and oxygen, but a simple substance, and that the former is a compound of this substance with hydrogen. The more general principle connected with these opinions, that oxymuriatic acid is like oxygen, an acidifying element, forming with inflammables and metals an extensive series of analogous compounds, leads still more directly to the subversion of the established chimical systems, and to an entire revolution in some of the most important doctrines of the science."Vol. i, p. 335.

Dr. M. did not over-estimate the importance of the opinions advanced by Davy, nor the revolution in chimical science which they were destined to produce. He contended against them for a time

with great ability and vigour, but the verdict in favor of Davy, though some time delayed, was at length unanimous !

In 1810 Davy was invited to give a course of chimical lectures before the Dublin society, which he did during the month of November of that year, and for which he received from the society five hundred guineas, or a little more than two thousand dollars. He also gave a similar course in Dublin the following year, and a course on geology, at the close of which he received from the provosts and fellows of Trinity College the honorary degree of LL. D. Subsequently, on the 8th of April, 1812, he received from his royal highness, the prince regent, afterward George the Fourth, the honor of knighthood, at a levee held at Carlton House.

The time now arrived for our philosopher to enter upon quite another sphere; and without entirely putting off the character of the man of science, to put on that of the gentleman. Alluding to the event just now mentioned, Dr. Paris remarks:

"On the day following this occurrence, Sir Humphry delivered his farewell lecture before the members of the Royal Institution; for he was on the eve of assuming a new station in society, which induced him to retire from those public situations which he had long held with so much advantage to the world, and with so much honor to himself. How far such a measure was calculated to increase his happiness I shall not inquire; but I am bound to observe, that it was not connected with any desire to abandon the pursuit of science, nor even to relax in his accustomed exertions to promote its interests. It was evident, however, to his friends, that other views of ambition than those presented by achievements in science had opened upon his mind: the wealth he was about to command might extend the sphere of his usefulness, and exalt him in the scale of society; his feelings became more aristocratic, he discovered charms in rank which had before escaped him, and he no longer viewed patrician distinction with philosophic indifference.

"On the 11th of April, 1812, Sir Humphry married Mrs. Apreece, the widow of Shuckburgh Ashby Apreece, Esq., eldest son of Sir Thomas Apreece; this lady was the daughter and heiress of Charles Kerr, Esq., of Kelso, and possessed a very considerable fortune."—Vol. i, P. 348.

Long before this time his friends had observed with pain the ill effects produced upon him by constant and excessive adulation. The change that was taking place in his former simple manners is first alluded to by our author immediately after his successful entrance upon the duties of his office in the theatre of the Royal Institution. Alluding to the praise bestowed so lavishly upon VOL. I.-39