Dec. g 1880] 



NATURE 



127 



he clearly brings forward his views concerning the union 

 of atoms to form the molecule. 



In 1S53 he published his interesting observations on 

 the conversion of yellow phosphorus into the red modifi- 

 cation by heating it to 200° in presence of mere traces of 

 iodine {Chcm. Soc: Joiirn. v. 2S9). Another \-er)' im- 

 portant and difficult investigation which occupied much 

 of his attention about this time was the question of the 

 purification {Ann. dc Chiniic, 45, 351) of graphite, and the 

 determination of its "atomic weight" (Phil. Trans. 1859, 

 249). By heating graphite with strong nitric acid and chlor- 

 ate of potash, Brodie showed that, unlike all the other modi- 

 fications of carbon, graphite yields a remarkable crystalline 

 acid, to which he gave the name of graphitic acid, having 

 the formula C11H4O;,. Tne existence of this interesting 

 body led Brodie to the conclusion that graphite may be 

 considered as a peculiar radical, to which he gave the 

 name of graphon. In the year 1S55 Brodie was appointed 

 Waynflete Professor of Chemistry in the University of 

 Oxford, a position which enabled him to throw all his 

 influence into forcing the recognition of chemical science 

 as a proper object of academic training. Under his fos- 

 tering care the science which had hitherto been so long 

 neglected put out distinct signs of life : new laboratories 

 and lecture-rooms were built, to which students flocked 

 in numbers, and Oxford saw the unwonted sight of her pro- 

 fessor of chemistry busily engaged in original investigation, 

 as well as in the tutorial duties of his chair. The dis- 

 covery of those singular and dangerous bodies, the perox- 

 ides of the organic radicals {Proc. Roy. Soc. ix. 361, Phil. 

 Trans. 1S63, 407), was made in the laboratory of the New 

 Museum. The same laboratory soon afterwards saw the 

 minute and careful investigation on ozone {Phil. Trans. 

 1S72, 432), which proved beyond doubt or cavil that the 

 supposition that the molecule of ozone is represented by 

 the formula O3 is both necessary and sufficient to explain 

 all the observed phenomena. 



Next we find him experimenting on the synthetic pro- 

 duction of the hydrocarbon methane, as well as of formic 

 acid, by the direct union of hydrogen and carbon monoxide 

 under the influence of the electric spark. Then he 

 ■examines the effect of an induced electric current upon 

 pure and dry carbonic acid, and proves that this gas is 

 partially decomposed with formation of carbon monoxide 

 and oxygen, the latter gas being converted into ozone. And 

 he then proceeds to ask whether the ozone thus produced 

 is identical with that obtained from ordinary oxygen, and 

 by a series of careful quantitative experiments demon- 

 strates the identity of the ozone from these two sources. 



This was Brodie's last experimental investigation. Ere 

 long he resigned the Chair of Chemistry at Oxford, 

 regretted by the whole University. He retired to his 

 charming seat on the summit of Box Hill. Neither his 

 own scientific activity nor his deep interest in the scien- 

 tific work of others ceased on his withdrawal from 

 professional life. Before his retirement he had put 

 forward {Pliil. Trans. 1S66, 781-860) in his " Calculus of 

 Chemical Operations," views altogether novel respecting 

 the nature of chemical change. In place of the usual 

 mode of considering this as due to a change in the 

 relative positions of the atoms of which matter is com- 

 posed, Brodie founds his theory of the constitution of 

 chemical elements and compounds on the simple volume- 

 relations discovered by Gay-Lussac to exist between these 

 substances in the gaseous state. To hydrogen Brodie 

 gives a simple symbol, because the unit of hydrogen can, as 

 he expresses it, be conceived as made at once by one 

 operation, whilst to oxygen he gives a double symbol, 

 because it cannot, according to him, be made by less 

 than two operations. The clement chlorine is supposed 

 to be made up of three operations, and a treble symbol is 

 given to this body. Concerning the probable or possible 

 decomposition of the elements Brodie naturally speculates. 

 His analysis had led him to suspect that "chemical sub- 



stances are really composed of a primitive system of 

 elemental bodies analogous in their general nature to our 

 present elements, some of which we possess, but of which 

 we possess only a few '' ('•' Ideal Chemistry,'' p. 54). But 

 no experimental evidence of this fact was offered by him, 

 and none of a satisfactory character was otherwise forth- 

 coming, until \'ictor Aleyer announced his belief that 

 chlorine was capable of undergoing decomposition at high 

 temperatures. 



Here was a proof of the truth of Brodie's complex 

 symbol ! .Sad to say, further experiment has not corro- 

 borated this conclusion. No substance dift'ering essen- 

 tially from chlorine has yet been got from this body. Even 

 the change of density at a white-heat appears in the case of 

 chlorine to be, to say the least, doubtful. So we are left 

 for the present, and the author of the " Calculus of Opera- 

 tions" is left for ever,without the experimental confirmation 

 of his conclusions which he so much desired. Whatever 

 may be the verdict of the future as to the value of Brodie's 

 Calculus, there is no doubt that science is indebted to him 

 for an altogether new view of chemical combination 

 obtained by a systematic analytical process. 



This occasion is not a fitting one to enlarge upon the 

 high personal character of the late Sir Benjamin Brodie. 

 Suffice it to say that in all relations in life, in the domestic 

 circle as in society, in the chair at Burlington House as 

 in that at Oxford, he displayed all those qualities of heart 

 and head which alone give dignity and sweetness to life, 

 the possession of which ensures for his memory a lasting 

 place in the minds of all those who were fortunate enough 

 to count him amongst their friends. H. E. R. 



THE PHYLLOXERA LX FRAXCE 



THE new vine-disease, due to the Pliyllo.vcra vastatri.r 

 Planchon, has already caused much damage to the 

 French vineyards and wine-production. From the taxes 

 arising from that national industry France derives a 

 considerable part of her revenue ; and this subject has 

 consequently occasioned innumerable publications and 

 investigations. Of the latter some have been empirical 

 and without result ; others, which were conducted scienti 

 fically, have alone been of any use. It was moreover 

 absolutely necessary to have an unswerving confidence in 

 exact observations, in order to persevere in making 

 experiments which are ofcen disturbed and rendered 

 apparently self-contradictory by the secondary and ever- 

 varying conditions of cultivation. These experiments 

 have at last been crowned with success, and now there are 

 decidedly good grounds for hope. For the last two years 

 the public have shown a steaddy increasing confidence in 

 scientific methods. 



One of the most distinguished chemists, a man of 

 whom France is proud, and with whom readers of 

 Nature are well acquainted, especially as they were 

 lately presented with his portrait and biography, iVI. 

 Dumas, applied himself to the study of the Phylloxera, 

 and pursued his task from day to day with keen deter- 

 mination, notwithstanding the attacks of some and the 

 discouraging advice of others. It is his well-intentioned 

 and unceasing diligence that we must thank for never 

 having lost heart ; it is to hinr that those results are due 

 which are presently to be indicated. When the pcbrine- 

 disease was raging on silkworms in the South of France, 

 it was by his personal suggestion and repeated encourage- 

 ment that ls\. Pasteur agreed to devote himself to that 

 difficult study ; and it is the same gentle influence and 

 guidance that have directed the present writer, together 

 with several others, especially MJNI. Balbiani, Duclaux, 

 and Mouillefert. 



Henceforward the principal problems raised by the 

 study of \ ine diseases are solved. They were solved one 

 after another in regular order, as fresh light appeared and 

 the ends to be aimed at became more definite. It cannot 



