April 24, 1902] 



NATURE 



587 



A Correction. 



In my letter re " Birds attacking Butterflies and Moths," in 

 Natire for March 6 (p. 415). there occur the words, " I con- 

 clude, therefore, that they were last year's birds, which knew 

 and disliked /). liuiniaie.'^ There is some slip here, for what 

 I meant to say was, " I conclude, therefore, that last year's 

 bird knew and disliked D. limiiiace." This, it will be seen, 

 agrees with the context ; I only used one Babbler last year, and 

 offered D. limiiiacc to this only. F. Finn. 



Indian Museum, Calcutta, March 27. 



SOME SCIENTIFIC CENTRES. 

 IV. — The Heidelberg Physic.\l L.\boratory. 



MOST travelled Englishmen are doubtless acquainted 

 with the ancient town of Heidelberg, so famous 

 for the beauty of its situation and the grandeur of its 

 ruined castle. But far fewer know the charms of the 

 long and' romantic valley of the Neckar, at the almost 

 sensational exit of which, from the Odenwald into the level 

 plain of the Upper Rhine, Heidelberg stands. So also it is 

 true that while most educated people connect Heidelberg 

 with the great names of Kirchhoffand Bunsen and their 

 epoch-making discoveries in spectrum analysis, it is only 

 the special students who know how large in extent and 

 how important in result and example is the work which 

 has steadily gone on for many years in the physical 

 laboratory in the Friedrichsbau. 



Its small beginnings in the middle of the last century 

 are marked by the name of Kirchhoff scratched on the 

 window of what is now the private room of the senior 

 assistant. From this window one may look out over 

 the Rhine plain towards busy Mannheim, as Bunsen 

 and Kirchhoff did one night when a fire was raging there, 

 and they were able by spectroscopic examination of the 

 flames to ascertain that barium and strontium were 

 present in the burning mass. But the same window also 

 looks across the Neckar to the Heiligenberg, along the 

 slopes of which runs the " Philosophers' Walk," the chief 

 of the many paths among the wooded hills around the 

 town, which the two friends were wont to traverse in their 

 daily "constitutionals." Bunsen is known to have said 

 that it was during such walks that his best ideas came to 

 him. One day the thought occurred, " If we could 

 determine the nature of the substances burning at Mann- 

 heim, why should we not do the same with regard to the 

 sun ? But people would say we must have gone mad to 

 dream of such a thing." All the world knows now what 

 the result was, but it must have been a great moment 

 when Kirchhoff could say, " Hunsen, I have gone mad," 

 and Bunsen, grasping what it all meant, replied, " So 

 have I, Kirchhoff ! " 



Kirchhoffs four-prism spectroscope, together with 

 other apparatus of his, is preserved in the collections of 

 the Laboratory, and well deserves the almost reverential 

 awe with which it was examined by a certain foreign 

 professor, who protested that objects of such historic 

 interest should be kept in a fire-proof safe. 



Kirchhoff, who in his later years suffered much from 

 ill health, left Heidelberg in ICS75 on his appointment as 

 professor of theoretical physics at Berlin, where, by the 

 way, he had no official laboratory, and carried on his 

 experimental work {e.g. the research on the conductivities 

 of the metals for heat and electricity) in the laboratory 

 of his friend von Hansemann. His successor at Heidel- 

 berg was his former pupil, Quincke, who has been 

 professor there ever since, and is now the " doyen " of 

 German physicists, both by length of service — for though 

 only sixty-seven he has been a professor for more than 

 forty years — and by the amount and variety of his 

 scientific work. It is true that this work has not been 

 of the kind that gets into the newspapers, but the real 

 students will certainly value it none the less on that 

 account, and even the beginner in science has heard of 



NO. 1695, VOL. 65] 



" Quincke's Interference Tube " and his standard 

 measurements of capillary constants. English students 

 may well take some special interest in Quincke, for his 

 personal relations with English men of science i^e.g. Lord 

 Kelvin and Sir Henry Roscoe) have been particularly 

 close ; he is never tired of dwelling with admiration on 

 the achievements of Young, Faraday and Kelvin — and 

 in the case of Young in particular of vindicating his 

 priority in respect of many of the ideas in light and 

 sound often regarded as original to Fresnel and Helm- 

 holtz — and nowhere have his own researches been more 

 highly valued than in this country, as is shown by the long 

 list of Universities (Cambridge, Oxford, Glasgow) and 

 learned societies (froin the Royal Society downwards) 

 which have conferred their honours upon him. 



Georg Hermann Quincke was born at Frankfort a. O. 

 in 1834 of partly Huguenot extraction. One who has 

 seen the diagrams, with circles worthy of Giotto, which 

 he draws on the blackboard, or had experience of his 

 apparently intuitive knowledge of the possibilities of the 

 most various materials and mechanical processes, might 

 well be inclined to regard this kind of power, so valuable 

 to the physicist, as an inheritance from some skilful 

 Huguenot ancestor. From 1852 onwards he studied at 

 Berlin, and then for a time at Konigsberg, attracted 

 thither (with others, such as Kirchhoff and Clebsch) by 

 the fact that F. E. Neumann was delivering the only 

 course of lectures on mathematical physics then to be 

 heard in Germany. Neumann's mathematical and ex- 

 perimental genius had considerable influence on Quincke, 

 and it was here that the profound interest in molecular 

 physics which has dominated his life-work was aroused 

 in connection with the theory of capillarity. But 

 Neumann allowed his pupils too little scope for origin-, 

 ality, and Quincke removed to Heidelberg, where (in 

 1854) Kirchhoff had just been appointed professor of 

 physics. Under him Quincke carried out (in 1856) his 

 first physical research, an investigation of the lines of 

 flow of an electric current from one point to another of a 

 metal plate. With a plate made of adjoining semicircles 

 of copper and lead, Kirchhoffs law of the refraction of 

 currents was confirmed, viz. that the tangents of the 

 angles of incidence and refraction are in a constant ratio, 

 though, curiously enough, this ratio was not found equal 

 to that of the conductivities of the two metals, as the 

 theory requires, but only about half as great. During 

 this time — in which Matthiessen and Roscoe were among 

 his fellow students — Quincke also worked much with 

 Bunsen, especially in gas and mineral analysis, and, in- 

 deed, his first published paper was on the red and grey 

 gneiss of the Erzgebirg (1856). Doubtless the associa- 

 tion with Bunsen did something to cultivate Quincke's 

 native faculty for the ingenious adaptation of the simplest 

 materials, of which more hereafter. 



From Heidelberg Quincke returned to Berlin, "promo- 

 vierte " in 1858, became " Privat docent " in 1859, in i860 

 was appointed professor at the Royal Prussian '' Gewerbe 

 Akademie " and in 1865 "ausserordentlicher " professor 

 at the University of Berlin, posts which he held till 1872. 

 His courses of lectures included the only one in mathe- 

 matical physics then given in Berlin. But as regards 

 original work the young professor was much hampered 

 by the fact that he had neither stores of apparatus nor 

 even a decent library of scientific literature at his dis- 

 posal. In both respects he was much aided by his friend 

 VVilhelmy (of invert sugar fame), who possessed a good 

 deal of apparatus brought from Paris, and by Mitscherlich. 

 Before this Mitscherlich had introduced him to G. 

 Wiedemann, and a beautifully kept juvenile note-book had 

 led to his drawing the figures for some of Wiedemann's 

 publications. How well he was capable of such work 

 will be clear to all who have seen his lithographed sheets 

 of instructions for practical work in use in his present 

 laboratory, with their admirable diagrams. 



