An Introduction to the History of Science

by Walter Libby

In the mean time Davy had been chosen superintendent of the Pneumatic Institution at Bristol by Dr. Beddoes, its founder. It was supported by the contributions of Thomas Wedgwood and other distinguished persons, and aimed at discovering by means of experiment the physiological effect of inhaling different gases, or "factitious airs," as they were called. The founding of such an establishment has been termed a scientific aberration, but the use now made in medical practice of oxygen, nitrous oxide, chloroform, and other inhalations bears witness to the sanity of the sort of research there set on foot. Even before going to Bristol, Davy had inhaled small quantities of nitrous oxide mixed with air, in spite of the fact that this gas had been held by a medical man to be the "principle of contagion." He now carried on a series of tests, and finally undertook an extended experiment with the assistance of a doctor. In an air-tight or box-chamber he inhaled great quantities of the supposedly dangerous gas. After he had been in the box an hour and a quarter, he respired twenty quarts of pure nitrous oxide. He described the experience in the following words:—

"A thrilling, extending from the chest to the extremities, was almost immediately produced. I felt a sense of tangible extension highly pleasurable in every limb; my visible impressions were dazzling, and apparently magnified; I heard every sound in the room, and was perfectly aware of my situation. By degrees, as the pleasurable sensations increased, I lost all connection with external things; trains of vivid visible images rapidly passed through my mind, and were connected with words in such a manner, as to produce perceptions perfectly novel. I existed in a world of newly connected and newly modified ideas: I theorized, I imagined that I made discoveries. When I was awakened from this semi-delirious trance by Dr. Kinglake, who took the bag from my mouth, indignation and pride were the first feelings produced by the sight of the persons about me. My emotions were enthusiastic and sublime, and for a minute I walked round the room perfectly regardless of what was said to me. As I recovered my former state of mind, I felt an inclination to communicate the discoveries I had made during the experiment. I endeavored to recall the ideas: they were feeble and indistinct; one collection of terms, however, presented itself; and with the most intense belief and prophetic manner, I exclaimed to Dr. Kinglake, 'Nothing exists but thoughts! The universe is composed of impressions, ideas, pleasures and pains!'"

Davy aroused the admiration and interest of every one who met him. A literary man to whom he was introduced shortly after his arrival in Bristol spoke of the intellectual character of the young man's face. His eye was piercing, and when he was not engaged in conversation, its expression indicated abstraction, as though his mind were pursuing some severe train of thought scarcely to be interrupted by external objects; "and," this writer adds, "his ingenuousness impressed me as much as his mental superiority." Mrs. Beddoes, a gay, witty, and elegant lady, and an ardent admirer of the youthful scientist, was a sister of Maria Edgeworth. The novelist's tolerance of Davy's enthusiasm soon passed into a clear recognition of his commanding genius. Coleridge, Southey, and other congenial friends, whom the chemist met under Dr. Beddoes' roof, shared in the general admiration of his mental and social qualities. Southey spoke of him as a miraculous young man, at whose talents he could only wonder. Coleridge, when asked how Davy compared with the cleverest men he had met on a visit to London, replied expressively: "Why, Davy can eat them all! There is an energy, an elasticity in his mind, which enables him to seize on and analyze all questions, pushing them to their legitimate consequences. Every subject in Davy's mind has the principle of vitality. Living thoughts spring up like turf under his feet." He thought that if Davy had not been the first chemist he would have been the first poet of the age. Their correspondence attests the intimate interchange of ideas and sentiments between these two men of genius, so different, yet with so much in common.

In 1801 Davy was appointed assistant lecturer in chemistry at the Royal Institution (Albemarle Street, London), which had been founded from philanthropic motives by Count Rumford in 1799. Its aim was to promote the application of science to the common purposes of life. Its founder desired while benefiting the poor to enlist the sympathies of the fashionable world. Davy, with a zeal for the cause of humanity and a clear recognition of the value of a knowledge of chemistry in technical industries and other daily occupations, lent himself readily to the founder's plans. His success as a public expositor of science soon won him promotion to the professorship of chemistry in the new institution, and through his influence an interest in scientific investigation became the vogue of London society. His popularity as a lecturer was so great that his best friends feared that the head of the brilliant provincial youth of twenty-two might be turned by the adulation of which he soon became the object. "I have read," writes his brother, "copies of verses addressed to him then, ... anonymous effusions, some of them displaying much poetical taste as well as fervor of writing, and all showing the influence which his appearance and manner had on the more susceptible of his audience."

His study of the tanning industry (1801-1802) and his lectures on agricultural chemistry (1803-1813) are indicative of the early purpose of the Royal Institution and of Davy's lifelong inclination. The focus of his scientific interest, however, rested on the furtherance of the application of the electrical studies of Galvani and Volta in chemical analysis. In a letter to the chairman of managers of the Royal Institution Volta had in 1800 described his voltaic pile made up of a succession of zinc and copper plates in pairs separated by a moist conductor, and before the end of the same year Nicholson and Carlisle had employed an electric current, produced by this newly devised apparatus, in the decomposition of water into its elements.

In the spring of the following year the Philosophical Magazine states: "We have also to notice a course of lectures, just commenced at the institution, on a new branch of philosophy—we mean Galvanic Phenomena. On this interesting branch Mr. Davy (late of Bristol) gave the first lecture on the 25th of April. He began with the history of Galvanism, detailed the successive discoveries, and described the different methods of accumulating influence.... He showed the effects of galvanism on the legs of frogs, and exhibited some interesting experiments on the galvanic effects on the solutions of metals in acids." In a paper communicated to the Royal Society in 1806, On Some Chemical Agencies of Electricity, Davy put on record the result of years of experiment. For example, as stated by his biographer, he had connected a cup of gypsum with one of agate by means of asbestos, and filling each with purified water, had inserted the negative wire of the battery in the agate cup, and the positive wire in that of the sulphate of lime. In about four hours he had found a strong solution of lime in the agate cup, and sulphuric acid in the cup of gypsum. On his reversing the arrangement, and carrying on the process for a similar length of time, the sulphuric acid appeared in the agate cup, and the solution of lime on the opposite side. It was thus that he studied the transfer of certain of the constituent parts of bodies by the action of electricity. "It is very natural to suppose," says Davy, "that the repellent and attractive energies are communicated from one particle to another particle of the same kind, so as to establish a conducting chain in the fluid. There may be a succession of decompositions and recompositions before the electrolysis is complete."

The publication of this paper in 1806 attracted much attention abroad, and gained for him—in spite of the fact that England and France were then at war—a medal awarded, under an arrangement instituted by Napoleon a few years previously, for the best experimental work on the subject of electricity. "Some people," said Davy, "say I ought not to accept this prize; and there have been foolish paragraphs in the papers to that effect; but if the two countries or governments are at war, the men of science are not. That would, indeed, be a civil war of the worst description: we should rather, through the instrumentality of men of science, soften the asperities of national hostility."

In the following year Davy reported other chemical changes produced by electricity; he had succeeded in decomposing the fixed alkalis and discovering the elements potassium and sodium. To analyze a small piece of pure potash slightly moist from the atmosphere, he had placed it on an insulated platinum disk connected with the negative side of a voltaic battery. A platinum wire connected with the positive side was brought in contact with the upper surface of the alkali. "The potash began to fuse at both its points of electrization." At the lower (negative) surface small globules having a high metallic luster like quicksilver appeared, some of which burned with explosion and flame while others remained and became tarnished. When Davy saw these globules of a hitherto unknown metal, he danced about the laboratory in ecstasy and for some time was too much excited to continue his experiments.

After recovering from a very severe illness, owing in the judgment of some to overapplication to experimental science, and in his own judgment to a visit to Newgate Prison with the purpose of improving its sanitary condition, Davy made an investigation of the alkaline earths. He failed in his endeavor to obtain from these sources pure metals, but he gave names to barium, strontium, calcium, and magnesium, conjecturing that the alkaline earths were, like potash and soda, metallic oxides. In addition Davy anticipated the isolation of silicon, aluminium, and zirconium. No doubt what gave special zest to his study of the alkalis was the hope of overthrowing the doctrine of French chemists that oxygen was the essential element of every acid. Lavoisier had given it, indeed, the name oxygen (acid-producer) on that supposition. Davy showed, however, that this element is a constituent of many alkalis.

In 1810 he advanced his controversy by explaining the nature of chlorine. Discovered long before by the indefatigable Scheele, it bore at the beginning of the nineteenth century the name oxymuriatic acid. Davy proved that it contained neither oxygen nor muriatic (hydrochloric) acid (though, as we know, it forms, with hydrogen, muriatic acid). He gave the name chlorine because of the color of the gas (χλωρός, pale green). Davy studied later the compounds of fluorine, and though unable to isolate the element, conjectured its likeness to chlorine.