jVoz'. 4, 1880] 



NATURE 



I r 



round again nearly to the same place. With gnn or rifle agains 

 a tree-stem, I have often been able to spot the intersection with 

 my aim beforehand, lap by lap ; the drift is to leeward. 



I take it the explanation is, that in passing round with the 

 wind, and by slightly falling, great impetus is gained, which is 

 slowed down by turning to meet and rise on the wind like a kite 

 (if near, this is seen). I have seen the albatross and gulls floating, 

 but this case or these cases exemplify a major problem of rising 

 as well steadily and without effort ; it is also a clearer problem, 

 the solution of which more or less solves the minor problems of 

 mere flotation. 



The line of flight is thus :— 



^ski&js! 



Sapakati, Sibsagor, Asam 



S. E. Peal 



Regelation 



It is stated in Nature, vol. xxii. p. 5S9, that Faraday gave 

 the name of Regelation to the phenomenon of two pieces of ice 

 freezing together. Surely this is an error ? It was in 1856 when 

 .Sir Joseph D. (then Dr.) Hooker, Professors Tyndall and Huxley, 

 and the present writer were in Switzerland together. Prof. 

 Tyndall asked us to suggest a suitable term for the process ; and 

 it was Sir Joseph Hooker who said he could think of none 

 better than Regelation. Prof. Tyndall instantly accepted it as 

 exactly conveying the meaning he required. 



Agassiz, however, in writing upon the difficulties of ascertain- 

 ing the temperatures of glaciers by introducing thermometers 

 into borings, alludes amongst others to " la difficulte d'extraire 

 les fragmens detaches qui se regelaient constamment " (" Etudes 

 sur les Glaciers," p. 203). This shows that a similar expression 

 had occurred to him as suitable for this phenomenon, as early as 

 1840, in which year his " Etudes " were published. 



George Henslow 



JOHANNES RUDOLF VON WAGNER 

 ■t^rE have already briefly alluded to the loss suffered by 

 • • chemistry in the sudden death from heart-disease 

 of Prof, von Wagner, which occurred at Wijrzburg, 

 October 4. Johannes Rudolf Wagner was born February 

 13, 1822, at Leipzig. As a student in the university of 

 his native city he made choice of chemistry as a profes- 

 sion, and supplemented the then somewhat limited advan- 

 tages of the Leipzig laboratory by a course of study at 

 Paris, whither students from numerous countries were 

 attracted by the brilliant lectures and investigations of 

 Dumas. His residence there was followed by a lengthy 

 journey to the various centres of scientific interest in 

 France, Belgium, Holland, and Germany, after which he 

 returned in 1846 to Leipzig to accept a position as assistant 

 in the chemical laboratory of the university. In 1851 he 

 was appointed Extraordinary Professor of Technical Che- 

 mistry at the Ntirnberg Polytechnic. In 1856 he accepted 

 a call to the Chair of Technology at the University of 

 Wiirzburg, a position which he occupied until the time of 

 his death. During this same time he also filled two 

 important offices, that of Director of the Technological 

 Conservatory at Wiirzburg, and (until 1868) that of Royal 

 Examiner of the establishments for Technical Instruction 

 in Bavaria. His peculiar abilities and wide rimge of 

 experience led to his being frequently sent abroad by the 

 Bavarian Government on scientific missions, notably in 

 1S58 to England and Holland, and in 1S61 to Paris. 

 The same reasons led to his being called upon to 

 play an important role in the International Exhibitions 

 of the past twenty years. He was successively appointed 

 on the juries for chemical products at the Exhibitions of 

 London (1862), Paris (1867), and Amsterdam (1S69). At 

 Vienna (1873) he was the Chief Commissioner of Bavaria, 



and at Philadelphia (1876) he was a leading member of 

 the German Commission. The marked services which 

 he rendered in connection with the Vienna Exhibition 

 were recognised by his sovereign, who raised him to the 

 nobility, and decorated him with the Order of the Crown. 

 Prof, von Wagner was the recipient likewise of numerous 

 decorations from most of the European countries. 



The career of Wagner has been one of unusual and 

 varied activity. Apart from the multifarious duties of an 

 executive character which we have briefly enumerated, 

 he found time to render to pure chemistry, and especially 

 to applied chemistry, services of incalculable value. 

 Like Poggendorff in physics and Kopp in pure che- 

 mistry, his inclination led him towards the literary side 

 of his favourite studies, and it is on his accomplishments 

 as an author that his fame chiefly rests. Still, as an 

 investigator Wagner possessed remarkable and many- 

 sided aptitudes, and his name is associated with nume- 

 rous researches, the majority of which aim at the practical 

 application of scientific facts, or seek to ascertain the 

 chemical nature of important industrial products. One 

 of his first investigations (1S47) was on yeast, and in- 

 cluded a thorough study of its nature and growth, and 

 especially of the influence exercised by the presence of 

 foreign bodies on the phenomena of fermentation. In 



1849 he commenced a research on the oil of rue, which 

 was carried on at various intervals, and to which we 

 owe much of our knowledge of the constituents of this 

 important essence. In 1850 he assigned to the alkaloid 

 conine the structure of a dibutyryl-amine, a formula 

 verified long after by Schiff's synthesis (1871) of 

 paraconine, and by Michael and Gundelach's brilliant 

 synthesis a few months since, of methyl-conine. Among 

 other noteworthy theoretical results, mention may be 

 made of his extensive monograph on polymeric isomor- 

 phism (1851), and his experiments in the same year 

 establishing the nature of mercur-ammonium compounds 

 as substituted ammonias — mercury replacing hydrogen — 

 by a distillation of the well-known " white precipitate" 

 with aniyl-mercaptan, which yielded sulphide of mercury 

 and hydrochloride of amylamine. Shortly after he 

 showed that the compounds imperatorin and peuce- 

 donine obtained from the roots of sulphur-wort and 

 allied plants were identical, and established their chemi- 

 cal nature as angelate of the hydrate of peucedyle. One 

 of Wagner's most important researches, commenced in 



1850 and taken up several times since, had for an object 

 the colouring-matters of fustic. In its course he dis- 

 covered morin-tannic acid, which in company with morin 

 gives to fustic wood its tinctorial properties. He studied 

 carefully its reactions and its derivatives ; and among the 

 latter discovered pyrocatechin, the product of the de- 

 structive distillation of the acid. In 1853 he undertook 

 a thorough examination of the oil of hops, separating 

 the different chemical components, and finding amongst 

 them quercitrin and inorin-tannic acid. At this epoch 

 he succeeded in obtaining the remarkable alloy formed 

 by the union of four parts of potassium with z\ parts of 

 sodium, which is liquid at ordinary temperatures, and 

 resembles mercury in appearance. In 1S67 he contri- 

 buted an interesting research on the rapid increase of 

 solubility of carbonates in water containing carbonic acid 

 under various pressures. At the same time he broached 

 a theory of the formation of deposits of a graphite, in 

 which he attributed it to a decomposition of cyanides in 

 nature analagous to that occurring in the manufacture of 

 soda. Among his more important analytical researches 

 were the determinations (i860) of the quantities of oil 

 present in the nuts and seeds of many forest trees. As 

 an able deviser of analytical methods Wagner exhibited 

 numerous proofs. Among these mention may be made 

 of the use of the iodine reaction for analysing chlorides 

 of lime (1S59), the use of iodine likewise for the deter- 

 mination of the alkaloids (1S61), the volumetric deter- 



