158 



NATURE 



IDec. 17, 1885 



distingu^s de votre pays." The rest of this letter is not 

 personal, but refers to the impossibility of separating 

 chemistry from physics, and to the important aid which 

 each of these sciences constantly obtains from the other. 



Andrews was as successful in his Professorship as he 

 had formerly been as a Practitioner. He soon gathered 

 large classes, alike for general chemistry and for practical 

 laboratory work. All his spare time, for the greater part of 

 e\-ery working day, was spent in his private laboratory. 

 Here he delighted to receive his scientific friends, and to 

 engage eagerly in conversation with them while his hands 

 were busy with the steady, deliberate construction or ad- 

 justment of apparatus for his ne.Kt research. His habits 

 were of an extremely temperate, almost abstemious, 

 character. From his earh' breakfast, to his somewhat 

 late dinner-hour, he never partook of either food or drink ; 

 and used to say that a man required only two meals a 

 day. It is to be feared that his persistence in this habit 

 in his later years tended materially to reduce his strength. 



He was elected to the Royal Society in 1849. In 1S52 

 (at Belfast), and again in 1S71 (at Edinburgh), he presided 

 over the Chemical Section of the British Association. 

 He was President of the Association in iS76(at Glasgow), 

 having declined the appointment in a former year in con- 

 sequence of the state of his health. He was a cor- 

 responding member of the Royal Society of Gottingen 

 and an Honorary Fellow of the Royal Society of Edin- 

 burgh. He received honorary degrees from various 

 Universities. But he valued this class of distinctions 

 simply as tokens of the esteem and good wishes of the 

 donors ; and in the somewhat delicate matter of a civil 

 title he shared the opinion, and followed the practice, ot 

 his cherished friend Faraday. In 1879 he resigned his 

 appointments in Queen's College, and thenceforth led a 

 very retired life, though still vividly interested in the pro- 

 gress of science, till his death on November 26 last 



The only purely literary works of Andrews, so far as 

 the writers of this notice are aware, were his two ex- 

 tremel>- thoughtful and learned Chapters of Contein- 

 porary History. The first, entitled Studium Generate, 

 was published in 1867, when attempts were being made 

 to cripple the usefulness of the Queen's Colleges. The 

 reasons for the appearance of the second, published in 

 1869 with the title Tlie Cliiireh in Ireland, are still too 

 painfully prominent to require special mention. 



Dr. Andrews married, in 1842, Jane Hardie, daughter 

 of Major Walker, of the 42nd Highlanders. He is sur- 

 vived by his widow, by three daughters, and by two sons, 

 the elder of whom is Major in the Devonshire' Regiment, 

 and the younger a member of the Irish Bar. 



His first published paper on a chemical subject is on 

 the composition of the blood of cholera patients. He 

 showed that it diftered from normal blood only by having 

 a smaller proportion of \vater. Much more important 

 both in itself and as showing the bent of his mind to the 

 borderland between Chemistry and Physics is a paper on 

 galvanic cells with strong sulphuric acid as the exciting 

 liquid. The question is of course really that of the elec- 

 trolysis of strong sulphuric acid, and Dr. Andrews showed 

 that the composition of the gas given off at the cathode 

 varies in a remarkable manner with the temperature. 

 This is quite in accordance with what we now believe as 

 to the constitution and dissociation of strong sulphuric 

 acid, but at the time the paper was written nothing was 

 known which could lead any one to suspect such a 

 variation. 



We now come to one of his great works — the deter- 

 mination of the heat evolved during chemical action. In 

 three series of investigations he determined the heat 

 given out in the formation of neutral, acid, and basic salts, 

 by the action of acid on base ; in the displacement of 

 one metal in a salt by another ; in the formation of 

 oxides ; and in the formation of chlorides. In this great 

 research we see the character of the man, his clear view 



of what was to be observed, his distinct recognition of the 

 sources of experimental error, and the simple but etifectual 

 means he took to get his results free from the effects of 

 such disturbing causes. Especially worthy of note is his 

 use of solutions so dilute that further addition of water 

 produced no sensible thermal change. 



The well-known experiments of Favre and Silbermann 

 were published not long after Andrews' first papers on 

 this subject. It is interesting to notice that where these 

 observers differ from Andrews, subsequent investigations, 

 particularly those of Berthelot and of Thomsen, have 

 shown that Andrews was right. 



In 1855 Andrews communicated to the Royal Society a 

 paper of great importance and interest on Ozone. This 

 remarkable substance had been studied by Schonbein, its 

 discoverer, Marignac, De la Rive, Berzelius, Williamson, 

 Freray and Becquerel, and Baumert, but its nature still 

 remained a mystery. Is ozone always the same thing, 

 or are the ozone of electrolysis, that of the electric 

 machine, and that formed during the slow oxidation of 

 phosphorus, different bodies very like one another in 

 properties .' 



Some experiments seemed to show that ozone contained 

 nothing but oxygen, others that it was an oxide of hydro- 

 gen containing a larger proportion of oxygen than water 

 does. The question was exactly of the kind to attract 

 Andrews and to call out his peculiar powers of investiga- 

 tion. 



By a series of experiments remarkable for simplicity 

 and delicacy, and perfect adaptation to the purpose in 

 view, he proved that " ozone, from whatever source 

 derived, is one and the same body, having identical 

 properties and the same constitution, and is not a com- 

 pound body, but oxygen in an altered or allotropic con- 

 dition." 



The investigation into the nature of ozone was con- 

 tinued by .Andrews and Tait, and the results published in 

 their paper On the Volicmetric Relations of Osone and the 

 Action of the Electrical Discltarge on Oxyi;e7i and other 

 Gases (Phil. Trans., i860). These results led directly to 

 the theory of the constitution of ozone now universally 

 held ; indeed that theory is distinctly stated by Andrews 

 and Tait, although not further discussed on account of its 

 supposed improbability. 



Among smaller works we may mention the discovery of 

 minute particles of metallic iron in various rocks, par- 

 ticularly basalts. 



None of his chemical papers can be read without some 

 new idea being communicated to the reader, however 

 well acquainted he may be with the subject. 



The investigation, however, by which Andrews is, and 

 will continue to be, best known, was that On the Con- 

 tinuity of the Liquid and Gaseous States of Matter 

 which formed the subject of the Bakerian Lecture in 

 1^69, and again in 1876. 



One of the earliest of Faraday's researches was de- 

 voted to the liquefaction of gases, and he succeeded with 

 all but a few, which were in consequence, till very re- 

 cently, distinguished as "non-condensable." But he 

 expressed the conviction, founded on experiment, that 

 even these could be liquefied by the conjoint action of 

 sufficient pressure and sufficient reduction of temperature. 



Another extremely ingenious experimenter, Cagniard 

 de la Tour, had approached the subject from the opposite 

 side ; and had shown that liquids, such as water and 

 sulphuric ether, could be changed into something which 

 was certainly not liquid, by sulScient rise of temperature 

 without any great increase in volume. 



Regnault, also, had measured with his unrivalled pre- 

 cision the compressibility of various gases ; and had 

 called attention to the curious differences which they 

 show in their modes of divergence from Boyle's Law. 

 And Natterer, by employing pressures of some thousands 

 of atmospheres, had arrived at other startling results. 



