DAVY, Sin HUMPHRY. 



DAVY, SIR HUMPHRY. 



UOM of Light, with a new Theory of Respiration ; on the Generation 

 of Oxygen Clan, tod the Causes of the Colours of Organic Bodies. By 

 Humphry Davy.' Most of the peculiar views developed in these essays 

 were speedily abandoned by the author ; indeed his brother admits 

 that many of the speculations, he might perhaps have said most, were 

 wild and visionary ; and adds, what will be readily admitted, " that 

 the wildest of them are moat natural to a young mind just entering 

 on the twilight of physical science, gifted with high powers and a vivid 

 imagination." 



His next recorded experiments relate to the existence of silica in 

 various plant*, especially in the epidermis of cane; and in 1800 be 

 published in 1 vol. 8vo a work entitled ' Researches, Chemical and 

 Philosophical, chiefly concerning Nitrous Oxide and its Respiration.' 

 In this work, which contained the details of numerous highly -interesting 

 experiments, he has minutely detailed the extraordinary effects pro- 

 duced both upon himself and others by respiring nitrous oxide, a gas 

 till then deemed irrespirable. This work also contains an account of 

 some extremely hazardous experiments which he made upon himself 

 in breathing carburetted hydrogen, carbonic acid gas, azote, hydrogen, 

 and nitric oxide : in these dangerous trials his life was more than once 

 nearly sacrificed. 



In 1801 Davy came to London, and on the 25th of April he gave his 

 first lecture at the Royal Institution. He began with the history of 

 galvanism, detailed the successive discoveries, and described the 

 different methods of accumulating it; and on the 31st of May 1802 

 he was appointed professor. From 1SOO to 1807 a great variety of 

 subjects attracted his attention, especially galvanism and electro- 

 rh< mical science ; the examination of astringent vegetable matter in 

 connection with the art of tanning, and the analysis of rocks and 

 minerals with relation to geology and to agricultural chemistry. In 

 November 1807 his second Bakerian lecture was read, in which he 

 announced the most important and unexpected discovery of the 

 decomposition of the fixed alkalis by galvanism, and of the metallic 

 nature of their bases, to which he gave the names of potassium and 

 eodium. Dr. Paris has well observed that " Since the account given 

 by Newton of his first discoveries in optics, it may be questioned 

 whether so happy and successful an instance of philosophical induction 

 has ever been afforded as that by which Davy discovered the compo- 

 sition of the fixed alkalis." From the year 1808 to 1814 the following 

 papers by Davy were read before the Royal Society, and published in 

 their ' Transactions :' ' Electro-Chemical Researches on the Decom- 

 position of the Earths; with Observations on the Metals obtained from 

 the Alkaline Earths, and on the Amalgam procured from Ammonia,' 

 read J une 30th, 1 303. ' An Account of some New Analytical Researches 

 on the Nature of certain Bodies, particularly the Alkalis, Phosphorus, 

 Sulphur, Carbonaceous Matter, and the Acids hitherto uncompoundcd; 

 v, ah some general Observations on Chemical Theory,' December 13th, 

 IbOS. 'New Analytical Remarks on the Nature of certain Bodies; 

 being an Appendix to the Bakerian Lecture for 1808,' February 1809. 

 'The Bakerian Lecture for 1809; on some New Electro- Chemical 

 Researches on various Objects, particularly the Metallic Bodies, from 

 the Alkalis and Earths, and on some Combinations of Hydrogen,' 

 November 16th, 18t<9. 'Researches on the Oxymuriatic Acid, its 

 Nature and Combinations, and on the Elements of Muriatic Acid; 

 with sotno Experiments on Sulphur and Phosphorus,' July 12th, 1810. 

 ' The Bakerian Lecture for 1810 ; on some of the Combinations ol 

 Oxymuriatic Add Qas and Oxygen, and on the Chemical Relations ol 

 tbuM Principles to Inflammable Bodies,' November 15th, 1810. 'On 

 a ComUuatiou of Oxymuriatic Qas and Oxygen Gas,' February 21st, 

 1811. 'On some Combinations of Phosphorus and Sulphur, and on 

 tome other Subjects of Chemical Inquiry,' June 18th, 1812. 'On a 

 New Detonating Compound,' November 5th, 1812. 'Some further 

 Observations on a New Detonating Substance,' July 1st, 1813. 'Some 

 Experiments and Observations on the Substances produced in diflcrcnl 

 Chemical Processes on Fluor Spar,' July 8th, 1813. 'An Account ol 

 some New Experiments on the Fluoric Compounds, with some Observa 

 lions on other Objects of Chemical Inquiry,' February 13th, 1814. 



After the enumeration of these important subjects, we cannot do 

 better than refer to them in the words of his brother and biographer 

 " I shall not," says Dr. Davy, " attempt an analysis of these papers 

 I shall give merely a ski tch of the most important facts and disco 

 veries which they contain, referring the chemical reader to the origina 

 for full Mtiafaction. After the extraction of metallic bases from the 

 fixed alkalies, analogies of the strongest kind indicated that the alka 

 line earths are similarly constituted ; and he succeeded in proving 

 this in a satisfactory manner. But owing to various circumstances o 

 peculiar properties, he was not able on his first attempts to obtain 

 the metals of those earths in a tolerably pure and insulated state for 

 the purpose of examination. On his return to the laboratory after 

 his UlueM, this was one of his first undertakings. He accomplished i 

 to a certain extent by uniting a process of MM. Bcrzclius and Pontin 

 who were then engaged in the nine inquiry, with one of his own. 15; 

 negatively ! ctnijiug the earths, slightly moistened, and mixed witi 

 red oxide of mercury, hi contact with a globule of mercury, he 

 obtained amalgams of their metallic bases ; and by distillation, with 

 peculiar precautions, he expelled the greater (art of the mercury 

 Even now, in consequence of the very minute quantities of the bases 

 which he procured, and their very powerful attraction for oxygen, h 



as only able to ascertain a few of their properties in a hasty manner, 

 hey were of silvery lustre, solid at ordinary temperatures, fixed at a 

 red heat, and heavier than water. At a high temperature they 

 bstractcd oxygen from the glass, and at ordinary temperatures from 

 be atmosphere and water, the latter of which in consequence they 

 eco m posed. 



" The names he proposed for them, and by which they have since 

 jcen called, were barium, strontium, calcium, and magnium, which 

 te afterwards altered to magnesium. 



" The same analogies were nearly as strong applied to the proper 

 earths ; and he attempted their decomposition in a simitar manner, 

 >ut not with the same success. By the action of potassium proof was 

 obtained that they consist of bases united to oxygen ; but whether 

 heso bases were inflammable substances merely, or metallic inflam- 

 mable substances, was yet a problem, which has since been solved by 

 he labours of Wb'hler, Bussy, and Berzelius. Analogy was in favour 

 of the latter inference, as was also the circumstance that the bases of 

 hese earths are capable of entering into union with iron ; and this 

 las been confirmed by the inquiries just mentioned as regards the 

 majority of them, all but the basis of silica, which yet remains 

 doubtful. 



" The application of these facts to geology was full of promise ; and 

 le indulged in the hope that they might serve to explain not only 

 some of the most mysterious phenomena of nature, as earthquakes 

 and volcanoes, and the combustion of meteoric stones and falling 

 stars, but might ultimately lead to a general hypothesis of the forma- 

 tion of the crust of the earth." 



His ideas on this last subject, which he afterwards in great measure 

 relinquished, may be seen in Dr. Davy's 'Life of Sir Humphry,' 

 voL i. p. 397. 



After effecting the decomposition of the fixed alkali?, Davy, 

 reasoning from analogy, conjectured that ammonia might also contain 

 oxygen, and his first experiments were favourable to this supposition ; 

 out they contained a fallacy. In his various papers on ' Oxymuriatic 

 acid and its compounds,' he establishes the views of Scheele respecting 

 its nature, and proves that the reasoning of Berthollet, which had 

 jeuenilly been admitted by chemists, was fallacious. He shows that 

 Oxymuriatic acid is not a compound, as supposed, of muriatic acid and 

 oxygen, but on undecomposed body, to which, ou account of its groeu 

 colour, he gave the name of chlorine. In 1810 ho published the first 

 volume of his ' Elements of Chemical Philosophy,' which, although 

 they bear marks of haste, contain much interesting matter: 110 further 

 portion of this work was printed. His 'Elements of Agricultural 

 L'heuiistry,' which appeared soon after, is a work containing much 

 useful matter, and replete with sound and practical views of tho 

 subject. 



One of his greatest inventions was that of the miner's safety i 

 the first paper in relation to which appeared in the ' PhiloKi 

 Transactions' for 1815, and the lost in 1817. 



JSir Humphry became president of the Royal Society iu 1820, and 

 be continued to contribute papers on subjects of great interest for 

 some years. Among the most curious of these, and full of promise as 

 to utility, were those which related to the modes of protecti: 

 copper sheathing of ships ; from causes however which even his 

 sagacity could not foresee, the plan proved abortive. 



We have thus given a very imperfect and slight sketch of tie 

 discoveries of this very extraordinary man and eminent chemist; a 

 list of his works, or at any rate the principal of them, will be found 

 at the end of Dr. Paris' s Life of him. With respect to his philo- 

 sophical character, the parallel which has been drawn between him 

 and Dr. \\ulliuiton by the late Dr. Henry, while it does justice to both, 

 presents the powers of Davy in s strong and clear point of vi. \v, uud 

 in the language of one who was deeply versed in tho sciences of which 

 he is speaking, and intimately acquainted with the philosopher whose 

 portrait he draws. 



" To those high gifts of nature which are the characteristics of 

 genius, and which constitute its wry essence, both these eminent men 

 united an unwearied industry and zeal in research, and 1ml 'its of 

 accurate reasoning, without which even the energies of g< nius are 

 inadequate to the achievement of great scientific designs. With these 

 excellence*, common to both, they were nevertheless distinguished by 

 marked intellectual peculiarities. Bolt), ardent, and cuthu.-iu.Ttic, 

 Davy soared to greater heights; he commanded H wider horizon, and 

 his keen vision penetrated to its utmost boundaries. His imagination, 

 in the highest degree fertile and inventive, took a rapid and ex' 

 range iu the pursuit of conjectural analogies, which he submitted to 

 close and patient comparison with known lact, aud tried by on appeal 

 to ingenious and conclusive experiments. He was endued with the 

 spirit and was a master of the practice of the inductive logic ; ami he 

 has left us some of tha noblest examples of the efficacy of that great 

 instrument of human reason in tho discovery of truth. He applied 

 it not only to connect clarses of facts of more limited extent and 

 ini| ..ilance, but to develop great and comprehensive laws, which 

 embrace phenomena that are almost universal to the natural world. 

 In explaining these laws he cast upon them the illumination of his 

 own clear and vivid conception ; he felt an intense admiration of the 

 beauty, order, and harmony which are conspicuous In the perfect 

 chemistry of nature ; and he expressed those feelings with a force of 



