May 2, 1 901] 



NA TURE 



17 



Rowland's own researches with his grating are summed 

 up in his map of the solar spectrum and his table of the 

 wave-lengths of the elements, published in 1893 {Phil. 

 Mag., July, 1893, reprinted from Astronomy- and Astro- 

 physics.) 



Of late years he gave much time and attention to 

 a system of multiple telegraphy ; this was shown work- 

 ing at the Paris Exhibition last year. 



Enough has been written, perhaps, to indicate the 

 debt physical science owes to Rowland ; it is said he 

 never received any regular instruction in physics ; he 

 was an engineer, and to this, in great measure, his 

 success is due. The accuracy of his work on the ohm 

 depends on the care he took to construct his induction 

 coils so that their dimensions could be accurately meas- 

 ured ; he dealt with the determination of the mechanical 

 equivalent as an engineering problem : he employed a 

 large mass of water and used steam power to rotate 

 his paddle at a speed sufficient to make the resulting 

 rise in temperature one that could be measured with 

 accuracy. 



The theory of the concave grating was his, but its 

 success was due to the fact that Rowland had made an 

 almost perfect screw ; the method he employed in this 

 in given in his article, " Screw,'' in the " Encyclopaedia 

 Britannica." 



He lived for his work, but in his earlier days he 

 was passionately fond of riding. Some years after the 

 publication of the paper on the mechanical equivalent 

 he was awarded a prize for it by one of the Italian 

 Academies ; about the same time he won a steeple 

 chase, riding his own horse ; he hardly knew which 

 event gave him the greater pleasure. Another time, 

 passing through England on his way home from the 

 Continent, he had three days to spare. One of these 

 was passed at Cambridge discussing electrical measure- 

 ments, the other two were spent in a hurried visit to 

 Exmoor to get a run with the staghounds. Twenty 

 years ago he v/as a frequent visitor to England, and 

 attended several of the meetings of the British Associ- 

 ation ; recently his visits were much less frequent. 

 His friends here were aware that he was not well ; 

 some few weeks ago it was known that he had had a 

 serious illness, but the news then was that he was 

 better and on the road to recovery ; however, an oper- 

 ation proved necessary, and he never recovered from its 

 effects. 



Thus within the last few months physical science is 

 the poorer by the deaths of two of the most brilliant of the 

 followers of Maxwell — Fitzgerald and Rowland ; two 

 who were foremost among those who have given to the 

 theory of Faraday and Maxwell the right to claim the 

 position of the theory of the electro-magnetic field. 



R. T. G. 



PROF. FRANCOIS MARIE RAOULT. 



FR.^NCOIS RAOULT, professor of chemistry at 

 Grenoble, died there on April i after a short 

 illness. In him France has lost one of her most 

 distinguished men of science, whose discoveries have 

 supplied material for theoretical considerations which, 

 within the past fifteen years, have had a most profound 

 influence on chemistry and physics. 



Raoult was born on May )o, 1830, at Fournes (Nord). 

 His father, an officer in the local customs' service of 

 Villers Cotterets (.'\isne), sent the boy to school at Laon, 

 with the intention of his afterwards entering Government 

 service. But Raoult's tastes lay in a different direction ; 

 and with the full consent of his father he finished his 

 school career at Paris, and entered the scholastic pro- 

 fession. He began his teaching career at the age of 23 

 in the Lycde at Reims, and was shortly afterwards trans- 

 ferred to the College of Saint Die ; while there he 



NO. 1644, VOL. 64] 



graduated as B. es Lettres, and B. ts Sciences, passed 

 his " Licencie" examination, and was appointed 

 " Agrege" of special secondary instruction. On present- 

 ing a thesis on " The Electromotive Forces of \'oltaic 

 Cells " he gained the title of " Docteur 6s Sciences 

 Physiques," and four years later, in 1S70, he obtained the 

 chair of chemistry at Grenoble, where he passed the rest 

 of his life in constant labour in teaching and research 

 during a period of 31 years. In 1889 he was elected 

 " doyen," or dean of the faculty, and was re-elected to this 

 important office four times. He occupied himself largely 

 during the last dozen years in the reorganisation of the 

 Faculty of Science, leading to the creation of a local 

 university at Grenoble in 1896. 



The auttior of this notice was once informed by Raoult 

 that he independently discovered Faraday's and Ohm's 

 laws ; he had begun to experiment on the passage of 

 electricity through solutions before he had acquired any 

 real knowledge of what had already been achieved. On 

 mentioning the fact to his scientific friends at Paris he 

 learned, to his great disappointment, that his discoveries 

 had been anticipated ; but he took comfort in the thought 

 that if he >vere able to make such discoveries, of which 

 the importance is universally recognised, he must also 

 be able to advance science in other directions. His first 

 scientific work, published as his thesis for the doctorate, 

 has already been mentioned ; it was published in 1863, 

 and until 1870 he devoted himself to a study of the 

 chemical effects of the electric current, trying to distin- 

 guish between the heat evolved by chemical reactions 

 and that due to the electric current in the voltaic cell. 

 From 1870 to 1886 his attention was given to subjects of 

 a more purely chemical nature, such as the extent of 

 inversion of cane sugar under the influence of solar 

 radiation ; the absorption of ammonia by saline solutions ; 

 the presence of copper and zinc in the animal organism ; 

 the carbonates of calcium, strontium and barium ; and the 

 influence of carbonic anhydride on respiration. His work 

 on the absorption of ammonia' led him to consider the 

 freezing-points of the saline solutions of that gas (1S78) ; 

 and from that date onwards he busied himself with the 

 freezing- and boiling-points of solutions in water and in 

 other solvents of salts and organic compounds, publishing 

 his results in no less than 57 memoirs in various scientific 

 journals. His last publication, " La cryoscopie," was 

 published in the present year {Collection Scientia, Carr^ 

 et Naud). 



Most of Raoiflt's apparatus was constructed with his 

 own hands ; he was rather given to accurate experimenta- 

 tion than to the evolution of theories. The vast mass of 

 evidence which he accumulated relative to the lowering 

 of the freezing-points and of the vapour-pressures of 

 solvents by the presence of dissolved substances made it 

 possible for van 't Hoff to draw the important deductions 

 relative to the connection of these phenomena with osmotic 

 pressure and with the ionic theory of Arrhenius, which 

 will ever shed lustre on his name. And to the practical 

 chemist Raoult's work furnished a means of determining 

 the molecular weights of non-volatile substances — 

 methods familiar to every student of chemistry. 



His labours met with ample, though tardy, recognition. 

 In 1889 he was awarded the Prix Lccaze, of io,ooo 

 francs ; and in the same year he was made correspondaHt 

 de I'lnstittit de France. In 1895 he received the biennial 

 prize of the Institute ; in 1892 he was the Davy medallist 

 of the Royal Society, and in 1S9S he was elected a Foreign 

 Fellow of the Chemical Society of London. He was 

 chosen Chevalier de la Legion d' Honneur in 1890, raised 

 to Officier in 1895, and last year obtained the much- 

 coveted title of Commandeur. He was a member of 

 many foreign academies and scientific societies. 



Though modest and retiring, Raoult's devotion to his 

 work, dignity of character and sweetness of temper 

 gained him many friends. He was not an ambitious 



