590 



NA TURE 



[April 24, 1902 



surface tension of such solutions increases with greater 

 concentration by a term proportional to the number of 

 equivalent weights of salt in the solution. For fused 

 solid substances he has measured the surface tension by 

 the methods depending on the weight of falling drops, 

 and on the size and form of drops formed on a tlat surface. 

 Employing, then, a quantity a"' which he calls the 

 "specific cohesion " of the substance (defined by ii'- = rL 

 [surface tension] density), he found the remarkable result 

 that ("to a degree of approximation closer than that 

 which holds good for Uulong and Petit's law of atomic 

 heats") all pure substances fall into one or other of six 

 classes the specific cohesions of which are in the ratio of \ 

 (e.g. phosphorus, sulphur, bromides, iodides) : i {e.g. 

 Hg, Pb, chlorides, nitrates, sugars) : 2 {e.g. water, Ag, 

 carbonates, sulphates) ; 3 [e.g. Zn, Fe) : 4 (K) : 7 (Na). 

 It may be noted that a- measures the capillary attrac- 

 tion of a fluid sphere of unit radius on unit mass at its 

 surface. That this quantity for various fluids is propor- 

 tional to I, 2, 3 ... is in remarkable contrast to the 

 fact that gravitational attraction is independent of the 

 nature of the substances involved. 



One of Quincke's most interesting and characteristic 

 researches relates to the motions produced in drops 

 clothed with oil films when an alkali is brought into 

 contact with the oil, forming soap, which locally disturbs 

 the existing surface tensions and causes a movement of 

 the drop. Quincke sees in this the explanation of the 

 movements of protoplasm. To quote his own words, 

 " Ich glaube gezeigt zu haben, dass der Zellinhalt (das 

 Protoplasma und derZellsaft) jeder Pflanzenzelle von einer 

 dtinnen Oelhaut bekleidet ist : dass dunne Oellamellen 

 mit festem und flussigem Eiweiss die Plasmamasse 

 durchziehen, und dass durch Einwirkung des alkalischen 

 Eiweiss auf das oelsiiurehaltige Oel periodisch 'Eiweiss- 

 seife ' entsteht, aufgelost und an der Grenze von Oel und 

 umgebender Fliissigkeit ausgebreitet wird. Diese period- 

 ische Ausbreitung der wassrigen Losung von Eiweiss- 

 seife gabdanndie physikalische Erkliirung derim Innern 

 der Pflanzenzelle beobachteten Bewegungserschein- 

 ungen." Quincke's most recent researches relate chiefly 

 to his favourite problems of molecular physics, but are, 

 for the most part, still unpublished. 



Reference has already been made to the Heidelberg 

 " Praktikum,'' or course of practical physics, for which 

 Quincke has devised many ingenious forms of simple 

 and cheap apparatus, which are yet capable of giving 

 surprisingly good quantitative results. Here one may 

 see an optical bench which, though chiefly made of a 

 half-metre scale and some cork, sealing wax and glass 

 strips, yet enables the student to make all the usual 

 measurements with mirrors and lenses, without dark 

 room, and with an accuracy equal to that obtainable with 

 apparatus many times larger and more expensive. Again, 

 Quincke has invented a form of reflecting galvanometer' 

 which costs some fifty shillings in all, but is sufficient for 

 all ordinary electric measurements, not merely for 

 learners, but also for research students. Want of space 

 forbids us to tell of the almost innumerable devices for 

 solving just those problems which confront so many of 

 our science teachers in England at this moment which 

 the Heidelberg laboratory contains. A word may be 

 spared for two seeming trifles which are astonishingly 

 useful. One is the lidless box used as a seat, giving 

 three different heights, according as it is placed on its 

 short, long or open side. A few of these can be combined 

 with a screw clamp or two in endless ways to serve as 

 supports for apparatus, &c. The other is a form of 

 trestle - (with the two slant legs at one end replaced by 

 one vertical one), which is very convenient as a support 

 for pendulums and other such apparatus. 



' Tlii^, toRcther with (^)uinckc's inv.iluable " Cathetometer Microscope," 

 is visil>ic on the t.-\blc behind the Professor's right arm in the jiliotograph 

 rcprctluced herewith. 



■-' Visible on the right of the photograph. 



NO. 1695, VOL. 65 J 



It is much to be hoped that Prof. Quincke may see 

 his way to publish his laboratory notes in book form, and 

 if he would accompany such a book with directions for 

 carrying out what a witty Heidelberg student described 

 ;is " Quincke's cork- wax-pfennig system," he would be 

 conferring a boon on many students and more teachers. 

 But we fear it is hardly likely that the claims on his 

 time as teacher and investigator will allow opportunity 

 for this to be done. 



EMILIEN JEAN RENOU. 



IV/r RENOU was born at Vendome, March 8, 1815, 

 -^'-'-' and, naturally, went to the Lycee there. He 

 entered the Ecole Polytechnique in 1835 and later the 

 Ecole des Mines, where he studied under Elic de lleau- 

 mont. He subsequently visited (German universities for 

 two years, especially the lectures of (iauss at Gottingen. 



From 1839-42 he was attached to the Scientific Commis- 

 sion of Algeria and published a" Description Gt-ologique 

 de I'Algerie." In 1846 he was directed to collect all the 

 information as to Morocco which he could find, and the 

 result was a valuable work, " Description de I'Empire du 

 Maroc." He made a second visit to Algeria, at his own 

 expense, to verify previous geographical determinations. 



In 1850 he resolved to devote himself almost exclusively 

 to meteorology, and he was one of the founding members 

 of the SocietL- Mtittiorologique in 1853. He has published 

 numerous papers in its Annuaircs. He acted as its secre- 

 tary for eleven years, not consecutive, and no less than 

 four times was elected to fill the office of president. 



In 1868 he was one of the members of a committee, 

 under the presidency of Charles .Ste. Claire Deville, for 

 the organisation of the observatory of Montsouris, 

 After the events of 1870-72, this establishment was 

 placed under .M. Marie Davy, and M. Renou had to 

 leave. 



In 1872 he was officially appointed director of a 

 laboratory for meteorological research, an office which he 

 held until his death. This establishment was first located 

 at Choisy le Roi, but in a few months it was moved to 

 Pare St. iMaur, to a locality rented by M. Kenou. On the 

 official establishment of the Bureau Central de Mt^teor- 

 ologie, M. Renou's station was selected as the central 

 station for the climate of Paris, and the instruments werq 

 moved to a plot of ground which was assigned to the 

 Bureau, and where they now remain. M. Renou has con- 

 tributed to the Auiiiilcs of the Bureau three important 

 papers on the climate of Paris. 



M. Renou deservedly received many honours, the 

 principal being Legion of Honour, Chevalier (1847), 

 Officier (1884), Officier de I'Acadt-mic (1873), ^"d Officier 

 de I'Instruction Publique (1S91). 



He died on April 6 at Pare St. Maur at the age of 

 eighty-seven ; and he has bequeathed his large library 

 to the public library of his native place, Vendome. 



R. H. S. 



NOTES. 



The first of the two annual soirees of the Royal Society will 

 be held on May 14. This is the soiree to which gentlemen only 

 are invited. 



The meeting of the Paris Academy of Sciences on April 14 

 was adjourned as a sign of respect for the lute Prof. A. Cornu, 

 whose untimely death w.is announced by the president in the 

 following words :—" The Academy of Sciences has suffered a 

 great loss. Prof. Cornu died on Friday, carried away rapidly by a 

 disease which no one could foresee would terminate so sorrow- 

 fully. Our colleague was lelatively young; he entered the 

 Lcole Polytechnique in i860 and was nominated a mem- 



