Afril 2 1, 1898] 



NATURE, 



591 



OUR ASTRONOMICAL COLUMN. 

 Comet Perrixe.— The following is a continuation of the 

 «phemeris of Comet Perrine for the ensuing week, from Prof. H. 

 Kreutz's computation : — 



1898. R.A. Dec. Br. 



h. m s. c / 



April 22 ... 23 48 19 ... +46 I5'0 ••• 0-64 



23 ... 53 37 ••• 46 5o"3 



24 .. 23 58 57 ... 47 24-3 



25 .. o 4 19 •■• 47 57"i 



26 ... 9 42 ... 48 287 ... o 58 



27 ... IS 6 ... 48 59-Q 



28 ... o 20 32 .. +49 28'I 



The Aurora Spectrum. — Prof. E. C. Pickering tells us in 

 a Circular (No. 28) of the Harvard College Observatory that 

 the attempts made at photographing the spectrum of the aurora 

 have proved successful, Mr. Edward S. King having obtained 

 two plates, one on April i, 1897, and the other this year on 

 March 15. On the first of these photographs four bright lines 

 were visible after an exposure of 147 minutes, but uncertainty 

 existed as to the wave-lengths of these lines. In the more 

 recent negative two biight lines were obtained after an exposure 

 of 141 minutes. The brightest of these extends from 3892 to 

 3925, the wave-lenglh of the second being 4285. Assuming 

 that these two lines were photographed in 1897, the wave- 

 lengths of the four lines then obtained would be 3862, 3922, 

 4288, 4694. 



As regards the first two lines, 3862 and 3922, nothing as yet 

 can be said, as visual observations of the aurora have not 

 extended so far. The line 4288 seems probably to be the same 

 as observed in previous aurorre by Lemstrom, Wijkander and 

 Oettingen, the wave-lengths given by them being 426, 428 and 

 424 respectively. The last of the four lines at 469 is a well- 

 observed aurora line, having been seen no less than nine times 

 by observers ; its probable origin is the hot carbon band, which 

 extends from 467-474 



Prof. Pickering mentions that the spectroscope employed to 

 obtain these photographs was not specially designed for the 

 purpose, but a new instrument is in course of construction with 

 which it is hoped better results will be obtained. 



The M0VE.MENT OF S0L.A.R Facul^. — By a minute study 

 of the magnificent series of observations on sun-spots, made by 

 Carrington and Sporer, the difiFerence between the times of 

 rotation of the spots in different latitudes has been determined 

 with great accuracy. Thus a strict relation was found to exist 

 between the angular velocity of any spot and its latitude, the 

 former decreasing as the latter increased. Duner further showed 

 that exactly a similar law existed in the case of the general 

 surface of the sun, but with this exception, that the velocities of 

 each latitude for latitude did not agree. An interesting inquiry 

 was then to investigate the behaviour of the faculre, which 

 recent photographic methods have shown are so numerous over 

 the solar disc. Faculte, as many observers of the sun know, are 

 not such stable phenomena as spots ; nevertheless Wilsing, after 

 a laborious investigation, came to the conclusion that they were 

 imbued with a velocity that was constant for all latitudes, and 

 equal to a movement of 14^ '27 in 24 hours. Belopolsky, at a 

 iater date, adopted a different method of investigation, and was 

 led to draw the conclusion that facuke obeyed the same law of 

 the variation of the angular velocity of rotation as the spots. 

 More recently WoHer, after a method somewhat analogous to 

 that employed by Wilsing, came to the same conclusion as that 

 arrived at by Belopolsky. 



In consequence of the high importance that would be 

 attached to a definite result of so interesting a problem, Dr. W. 

 Stratonoff has undertaken a very complete investigation of the 

 whole subject, using as his data the fine photographs that have 

 been obtained in the last few years {^Meinoires cie I' Acadiniie 

 Imperiale des Sciences de St. Pelersbotirg. Classe Physico- 

 Mathematique, vol. v. No. 11). Out of a total number of 400 

 plates, for the years 1891-1894, he used 234 for this research, 

 as will be seen from the following list, showing by whom they 

 were taken : — 



1891 

 1892 

 1893 

 1894 



60 



57 

 76 



41 



Belopolsky. 



,, and Stratonoff. 



Stratonoff, Orbinsky and Evdokimoff. 



Total 234 



NO. i486, VOL. 57] 



We cannot enter at length into the details of the method M. 

 Stratonoff has employed in this long investigation, but must 

 confine ourselves simply to the results obtained. The measure- 

 ments of the heliographic latitudes and longitudes of each of the 

 1062 facul* employed are given in the conmiunication in one 

 table, while a second is confined to the heliographic latitude of 

 each facula with its angular velocity of rotation. The sum total 

 of the research is that Wilsing's result is not corroborated, for it 

 is found that the facula in different latitudes do not move with a 

 constant velocity ; in fact, the variation of the angular velocity 

 of rotation must be represented by a more complicated law than 

 that in use for the spots. For latitudes o°-8^ the angular 

 velocity of the faculre remains nearly constant ; from 9°-l6° it 

 decreases rather rapidly to the extent of nearly o°'4 ; for some 

 range of latitude the velocity becomes again nearly constant, 

 tending to increase rather than decrease. A rapidly slowing 

 down of about o°-5 takes place between latitudes 25° to 34°, and 

 after that in higher latitudes a very gradual diminution in velocity 

 is noticed more pronounced than was the case in the equatorial 

 zone. Thus it will be seen that velocities of rotation at the 

 highest and lowest latitudes differ by nearly a degree, the 

 characters of this variation being the same for both hemispheres. 

 Spots, it may be added, have the tendency to diminish the 

 velocity of rotation of faculae. As regards the movements of 

 faculee, spots, and the solar surface, the facula in all latitudes 

 have the greatest velocity of rotation ; then come the spots which 

 move more slowly, and lastly the solar surface, which has the 

 least movement of all. M. Stratonoff suggests that perhaps 

 these facts owe their origin in their difference of heights above 

 the envelope of the sun. The author concludes his interesting 

 paper with a series of instructive curves which convey very 

 clearly to the eye the results of the investigation. 



YEA ST AND ALCOHOLIC FERMENT A TION. 

 'pHOUGn the knowledge of the existence of alcoholic fer- 



-*- mentation and the preparation of alcoholic liquids dates 

 back to very remote antiquity, it is only within comparatively 

 recent times that an accurate acquaintance with the actual 

 nature of the process has been obtained. By the older writers 

 many processes have been confused together under the name 

 fermentation, though they have nothing in common but the 

 evolution of gas which takes place as they go on. The true 

 alcoholic fermentation, the formation of gas in the intestines of 

 animals, and the effervescence which takes place when an acid is 

 poured upon chalk, have all thus been grouped together as com- 

 parable phenomena. Of these different processes, however, that 

 of alcoholic fermentation has been made most widely a subject of 

 study, and from about the end of the seventeenth century definite 

 views as to what it really consists of have been entertained by 

 scientific men. 



The correspondence between the alcoholic fermentation of the 

 wort of beer, the must of wine and other saccharine Hquids, and 

 the disengagement of a gas under the influence of leaven in the 

 manufacture of bread, had been noticed at a considerably earlier 

 period. Very strange ideas were entertained as to the nature 

 and action of the leaven. It was by some writers held to be of 

 the same nature as that of the hypothetical philosopher's stone, 

 and just as the latter was supposed to be able to transmute all 

 metals by contact with them, .so the leaven was considered to be 

 able, in some occult way, to transform the dough into something 

 resembling itself. One fact of importance comes out amidst all 

 the mass of confusion, though its interpretation leaves much to 

 be desired. This is the discovery that a very small quantity of 

 leaven is capable of transforming an almost indefinite amount of 

 the dough. The dough wa<, however, thought to be converted 

 into leaven, and the capability established was distorted into a 

 mark of identity with the philosopher's stone. 



It was known, too, at an early date that besides an evolution 

 of gas, alcoholic fermentation is always accompanied by the 

 formation of a deposit in the fermenting liquid, which takes the 

 form sometimes of a sediment, sometimes of a scum floating on the 

 surface. By many writers considerable importance was attached 

 to this deposit, and to it was attributed some special occult force 

 capable of determining the changes which could be observed. 

 These changes were held by some investigators to be chemical 

 in nature, but still to be altogether different from ordinary 

 chemical reactions. Valentin ^ who wrote towards the close of 

 the sixteenth century, suggests that the deposited matter com- 

 municates to the liquid a kind of internal inflammation, and 



