May 19, 1910J 



NATURE 



345 



is frequently little left of the original foundation, yet 

 each structure represents an advance upon that which 

 it supersedes. Sir William Huggins recorded in 1867 

 that he had detected the presence of water vapour in 

 the atmosphere of Mars, and re-aflirmed his observa- 

 tion later at his observatory at Tulse Hill, but critical 

 inquiry afterwards showed that the conclusions had 

 been drawn too hastily. While, however, those 

 observations must be discarded, we have the recent 

 investigations at Prof. Lowell's Flagstaff Observa- 

 torv giving clear evidence of the presence of aqueous 

 vapour in the Martian atmosphere. So, like a coral 

 on its base, rises the living body of science upon the 

 monument of past effort. Cemented upon the rock 

 of nature. Sir William Huggins stretched out his 

 hands toward the stars, and if a succeeding genera- 

 tion is able to examine the secrets of the heavens 

 more closelv than was possible in earlier days, let it 

 remember the patient pioneer work required to form 

 the base of the pinnacle from which obsers'ations can 

 now be made. R. A. G. 



PROF. STANISLAO CANNIZZARO. 



BY the death of Cannizzaro, another link between 

 the chemistry of to-day and that of the mid- 

 Victorian era has been broken — a link which perhaps 

 more than any other served to connect two well- 

 defined and sharply differentiated epochs in the history- 

 of nineteenth-century chemistry. Cannizzaro was not 

 a great discoverer in the ordinary sense of that word ; 

 the number of his published researches is few, and 

 the field of inquiry he cultivated comparatively re- 

 stricted. His greatest discovery, indeed, was his own 

 countryman, Amedeo Avogadro. The fundamental 

 conception of Avogadro that the gaseous laws of 

 chemical combination — the laws associated with the 

 names of Dalton and Gay-Lussac — could be explained 

 by the simple hvpothesis that equal volumes of gases, 

 under identical conditions of temperature and pressure, 

 contain the same number of molecules was as the 

 seed which fell upon stony ground. Even the efforts 

 of Ampere — a man of far more influence in his genera- 

 tion — to cause it to fructify had no immediate effect. 

 Berzelius, for a time, dimly apprehended the poten- 

 tiality of the supposition, but he eventually lost his 

 way under the blind guidance of dualism, and led 

 Europe wrong for a quarter of a century. The 

 German school, it is true, mainly under the direction 

 of Gmelin, gradually shook itself free from dualism, 

 but it wandered still further from the true faith, and 

 by the middle of the nineteenth century chemical 

 theory was utterly befogged, and its doctrine bristled 

 with inconsistencies, contradictions, and anomalies. 



Cannizzaro appeared at the psychological moment, 

 as the phrase goes. In its effect, the publication, in 

 1S58, of his " Summary of a Course of Chemical 

 Philosophy " created a revolution in chemical thought 

 hardly less momentous than that which followed the 

 appearance of Dalton 's "New System." The pub- 

 lication of a svllabus of a lecture course is a simple 

 enough occurrence, and perhaps never before marked 

 an epoch. But its effect in this case was instantaneous 

 and profound. Cannizzaro demonstrated that the 

 hypothesis of his forgotten countryman constituted 

 the means of placing the most important of all 

 chemical constants on a definable basis ; it rendered 

 our conceptions of atoms and molecules, atomic 

 weights and equivalents, gaseous volumes and 

 valency, and all that is associated with or consequent 

 upon these conceptions, logical and consistent. 



It is not too much to sav that Cannizzaro's inter- 

 vention at this time saved the position of the atomic 

 theory. The early 'sixties of the last century were a 



NO. 2 II 6, VOL. 83] 



period of much perturbation ; there was then a sort 

 of parting of the ways. Williamson laboured to stem 

 the tide of infidelity, but many were unconverted, and 

 some even hardened their hearts. We hear little or 

 nothing to-day of the scepticism which was fashion- 

 able among the young bloods of fifty years ago. It 

 is largely due to Cannizzaro that our faith has been 

 strengthened and purified. 



There is something dramatic in the circumstance 

 that Cannizzaro should have passed away at the time 

 that all Italy is celebrating the achievements of Gari- 

 baldi and his never-to-be-forgotten Thousand in effect- 

 ing the establishment of ItaHan unity, a cause in 

 which Cannizzaro had himself struggled and suffered, 

 and in which he was destined to take a share in 

 shaping to a successful issue. 



Cannizzaro was born at Palermo rn 1826, where 

 his father was president of the High Court of Chan- 

 cery. He was originally intended for medicine, but 

 under the influence of Melloni he began the study of 

 natural science, more particularly chemistry, under 

 Piria, in whose laboratory he became preparateiir. 

 The revolution of 184S found Cannizzaro in Messina, 

 and the youth of twenty-two an officer of artillery and 

 a member of the Sicilian Parliament. For nearly 

 nine months the revolutionaries held out against Fer- 

 dinand's armv, but Messina was eventually bom- 

 barded and sacked, and Cannizzaro and what re- 

 mained of his band were driven to Tacrmina. With 

 the disaster of Novara and the abdication of Charles 

 Albert, the Sicilian movement collapsed ; the insur- 

 gents retreated to Catania, and thence by Castro- 

 giovanni to Palermo, where Cannizzaro succeeded in 

 getting on board a Sicilian frigate, and in escaping 

 to Marseilles. He was now almost destitute, but 

 friends helped him to Paris, and, thanks to Cahours, 

 he found a place in Chevreul's laboratory in the 

 Jardin des Plantes, and began the study of the amines 

 in conjunction with Cloez. In 185 1 he became pro- 

 fessor of physical chemistry at Alessandria, in Pied- 

 mont, where he discovered benzyl alcohol and worked 

 with Bertagnini on anisic alcohol. In 1855 he was 

 elected to the chair of chemistry at Genoa, where he 

 drew up the famous " Summary " of which mention 

 has been made. 



At this time the cause of Italian unity was in the 

 ascendant, and by i860, thanks to the affairs of 

 Magenta and Solferino. the consolidation of Central 

 Italy was complete. Sicily was once more ablaze, 

 and before, the middle of May Garibaldi and the 

 " Mille " had effected its liberation. Cannizzaro 

 immediately returned to Palermo, and threw himself 

 into the work of organising the political future of the 

 island and its relation to Italian unity. He then re- 

 sumed his academic work at Genoa, but in the follow- 

 ing year he was invited to the chair of chemistn,- at 

 Palermo, where he remained ten years, taking an 

 active share in the management of the University 

 and serving for a time as rector. 



In 1871 he was called to the University of Rome, 

 and made a senator of the kingdom. As director of 

 the Chemical Institute at Panisperma he gave, session 

 after session, for nearly forty years, svstemalic 

 courses of lectures on general and organic chemistrv, 

 and practically every Italian chemist of note now 

 living passed through his laboratories and worked 

 under his inspiration and direction. 



Cannizzaro was a foreign member of many learned 

 societies, and of nearly every academv in Europe. 

 At the time of his death he was the oldest foreign 

 member of the Chemical Societ}- of London, having 

 been elected in 1862. In .1872 he delivered the Fara- 

 day lecture to the society, giving a charming and 

 graceful exposition of the genesis of the doctrine with 



