The Discovery of the Alkali Metals by Humphry Davy: the Bearing of the Discovery Upon Industry

View Article Online / Journal Homepage / Table of Contents for this issue THE DISCOVERY OF THE ALKALI METALS BY HUMPHRY DAVY: THE BEARING OF THE DISCOVERY UPON INDUSTRY. BY F. MOLLWO PERKIN, PH.D. (A Paper read before the Faratlay Society, Tuesday, Dccenrber 17, 1907, Dr. H. BORNSin the Chair.) Humphry Davy was born on December 17, 1778, at Penzance. The Davys originally came from Norfolk, but settled down some generations earlier in Cornwall. Edmund Davy, the grandfather of Humphry, was a builder in the west of Cornwall, and Robert, his father, had a small property at Varfell, but he was thriftless, and when he died his affairs were found to be in a very embarrassed state ; so that upon Humphry, the eldest son, who at the time of his father’s death was sixteen years of age, fell the responsibility of looking after the family. Before this time Davy appears not to have been very studious, but of rather a restless disposition and by no means fond of restraint, but upon the death of his father he at once settled down to hard work and study, and a few weeks afterwards was apprenticed to an apothecary and surgeon who practised in Penzance. Not only did he whole-heartedly throw himself into the study of his profession, but he also mapped out for himself an arduous course of general study. In 1797 he commenced the study of natural philosophyand turned his attention to chemistry, as it helped him in the work of his profession. From the reading of chemistry to the practice with such crude apparatus as tea- cups and tobacco pipes was but a step, but beyond the fact of spoiling his sister’s dress with acids and frightening his friends by the noises of explosions Published on 01 January 1908. Downloaded by University of Prince Edward Island 26/10/2014 18:52:29. which proceeded from his experinienting room, little is known of the outcome of his work at this time, which, in any case, was probably not much more than seeking in the dark with but little light to guide him. It was meeting with Gregory Watt, the son of the engineer James Watt, who had been educated at the University of Glasgow, that finally decided Davy to devote himself to science. Mr. Gilbert, who afterwards occupied the Presidential Chair of the Royal Society in succession to Davy, helped him also by allowing him the use of his library and physical apparatus In 1798 Dr. Beddoes, who had been trained as a medical man, and had many strange and unpractical ideas, founded a kind of sanatorium in Bristol, which he called the Pneumatic Institution, and asked Davy if he would take charge of the laboratories. The main object of the Institution was to study gases and their effects upon different ailments. Davy, with his energetic disposition, threw himself heartily into the work, and in 1799 we find him studying the action of nitrous oxide upon the human system. He first of all experimented upon himself and then tried its action upon others. About this time Maria Edgeworth, who was visiting her sister, Mrs. Beddoes, wrote :- ‘‘A young man. a Mr. Davy, at Dr. Beddoes’, who has applied himself 205 View Article Online 206 DISCOVERY OF ALKALI METALS BY H. DAVY: much to chemistry, has made some discoveries of importance, and enthusi- astically expects wonders will be performed by the use of certain gases, which inebriate in the most delightful manner, having the oblivious effects of Lethe and at the same time giving rapturous sensations of the Nectar of the Gods. Pleasure even to madness is the consequence of this draught.” She adds, however, that some found nothing but a sick stomach and ;I giddy head. Although there are many points of great interest in Davy’s early days and in the gradual development of his power as he went on from step to step until he matured into one of the most brilliant experimenters, if not the most brilliant, which the nineteenth. century was to see, it is not my intention to describe the life of Davy, but to dwell upon his researches in connection with electrochemistry and to indicate the enormous progress in industry which Published on 01 January 1908. Downloaded by University of Prince Edward Island 26/10/2014 18:52:29. SIR HUMPHRYDAVY. has been gradually evolved from his small, but record-breaking, com- mencements. In October of 1800 he wrote a letter to Mr. Gilbert, addressed from the Pneumatic Institution, in which he refers to experiments upon galvanism. This letter is of particular importance, because it fixes the date at which he commenced to work at electrical phenomena, and which, as it afterwards turned out, was to be the monument of his most enduring fame. He says in this letter :- “Galvanism I have found, by numerous experiments, to be a process purely chemical, and to depend wholly on the oxidation of metallic surfaces, having different degrees of electric conducting power. “Zinc is incapable of decomposing pure water ; and if the zinc plates be kept moist with pure water, the galvanic pile does not act ; but zinc is capable of oxidating itself when placed in contact with water, holding in solution View Article Online REARING OF THE DISCOVERY UPON INDUSTRY 207 either oxygen, atmospheric air, or nitrous or niuriatic acid ; and under such circumstances the galvanic phenomena are produced, and their intensity is in proportion to the rapidity with which the zinc is oxidated. “The galvanic pile only acts for a few minutes, when introduced into hydrogen, nitrogen, . that is, only as long as the water between its plates holds some oxygen in solution : immerse it for a few seconds in water con- taining air and it acts again.” This shows that Davy had already a very acute insight into the working of the primary battery, and in this connection it must be born in mind that it was only in May, 1800, that the discovery of the Voltaic pile was made known by Volta in a letter to Sir Joseph Ranks, the then President of the Royal Society. On February 16, 1801, Davy was clected to the post of Assistant Lecturer in Chemistry at the Royal Institution, Director of the Laboratory and Assistant Editor of Journals of the Institution. It is of particular interest to notice that the first lecture lie gavc was upon “Galvanic Phenomena.” Davy at this time was rather ungainly in appearance and not particularly taking in manner. So much so, in fact, that Count Runiford, the head of the Royal Institution, was by no ineatis prepossessed when he first met him. But after hearing him lecture he exclaimed, Let him command any arrangements which the Institution can afford.” The chemist appointed to the Royal Institution in those days had not 311 altogether enviable position, because the Board of Managers were wont to meet and draw up suggestions as to the class of work which should he lectured upon and upon which research work should be carried out.::: Davy was, for example, asked to lecture upon the “ Principlcs and Art of Tanning,” then upon “ Agriculture,” and the work entailed upon these subjects must have prevented him from giving so much time as he probably otherwise would have done to the subject of electricity, although in 1806, in the Bakerian Lecture before the Royal Society, the subject of his paper was upon the decompositions and chemical changes produced in substances of known composition by electricity. He had also shown that it was due to impurities in the water used by Nicholson and Carlisle when they succeeded in deconiposiiig it electrolytically, that caused the appearance of acidity at the positive electrode Published on 01 January 1908. Downloaded by University of Prince Edward Island 26/10/2014 18:52:29. and alkalinity at the negative electrode. Beside this he had advanced his theory of electro-affinity, so that it is obvious he had had the subject of electricity and its applications to chemistry continually before him. In October, 1807, he commenced the study of the action of Voltaic electricity upon the alkalis, a subject which he had evidently considered before, because we find in one of his note-books under thc date August 6, 1800 :- (‘Would not potash dissolved in spirits of wine become a conductor ? ” To-day we know that potash dissolved in absolute alcohol is an electrolyte, although an extremely poor one. On November 19, 1807, Davy delivered the Bakerian Lecture before the Royal Society and astonished the scientific world by describing the metals potassium and sodium.+ The lecture was entitled, “ On some New Phenomena of Chemical Changes produced by Electricity, particularly the Decomposi- tion of the Fixed Alkalies, and the Exhibition of the New Substances which * The Royal Institution was originally founded on philanthropic lines to benefit the poor. t The first intimation of his discovery is found in his laboratory note-book, preserved at the Royal Institution under the date October 19, 1807. View Article Online 208 DISCOVERY OF ALKALI METALS BY H. DAVY: constitute their Bases ; and on the General Nature of Alkaline Bodies (Pld. Traits., 1808, vol. 98, pp. 1-44). Davy commenced by referring to the lecture delivered by hini the previous year where he described a number of deconipositions and chemical changes produced in substances of known composition by electricity, when he also stated with prophetic foresight that “the new methods of investiga- tion promised to lead to a inore intimate knowledge than had hitherto been obtained concerning the true elements of bodies.” He then describes the “ methods used for the decomposition of the fixed alkalies.” The first attempts were made upon saturated aqueous solutions of the metallic hydroxides, using the highest electrical power he could command.

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