42 



NATURE 



[Nov. 14, 1878 



presents so great a mixture of races, though the two 

 main divisions are Afghans proper and Tajiks. The 

 former name is applied to all those tribes that speak 

 Pushtu or Pukhtu, the other to those of the people 

 whose native language is Persian. To the latter are also 

 given the names Parsivan and Deggan or Dekkan. The 

 Afghans are mostly pastoral, while the Tajiks are seden- 

 tary and cultivate the soil. To these two great classes 

 must be added the Hindkis, of Hindu origin, and speak- 

 ing Hindustani, very numerous in the eastern districts ; 

 also the Hezareh, a people with Mongol features but 

 speaking Persian, found mainly between Ghazna and 

 Herat. The Kisil-bash or "Red Heads," although not 

 yery numerous, are an important factor in the popula- 

 tion. They are not Persian by origin, as is commonly 

 stated, but belong to one of the Turcoman tribes of 

 Persia. There has been much discussion as to the origin 

 of the Afghans, no doubt the true aborigines of the 

 country. Some have sought to find in them the descend- 

 ants of the captive ten tribes of Israel ; but this is a 

 mere fanciful Mussulman tradition. Their language, at 

 least, proves that they belong to the great Indo-European 

 family, and that in this family they are specially allied to 

 the Iranian group, but with a linguistic development 

 peculiar to themselves, showing also the influence of 

 Sanscrit. Moreover, it can be conclusively established, 

 both by historical and ethnological evidence, that from 

 the most ancient times the Afghans have inhabited the 

 basin of the Cabul river, which is still the principal seat 

 of the race. The true national name of the Afghan 

 people, the name recognised by themselves, is that of 

 Pashtoun, Pakhtoun, or Poukhtaneh. In physical type 

 the Afghans, like all the other peoples of Western Asia, 

 approach the European conformation ; the difference 

 being in physiognomy, not in type. Like most other 

 primitive peoples, the social organisation of the Afghans 

 is based on the tribe or clan, and in many respects, it has 

 been said, resembles the old clan system of the Scottish 

 Highlands. 



OUR ASTRONOMICAL COLUMN 



The Solar Eclipse of 1879, July 19. — Though the 

 second of the solar eclipses of next year will not be 

 actually total at any point upon the earth's surface, the 

 difference between the geocentric diameters of sun and 

 moon is sufficiently small to allow of the effect of the 

 augmentation upon the latter, bringing up the phase to 

 one nearly approaching totality in those parts which have 

 the sun close upon the meridian. In the longitude of 

 Aden, or rather, upon the opposite coast of Africa, about 

 Zeyla, the moon's augmented semi-diameter will be only 

 four seconds less than that of the sun, and though the 

 eclipse thus remains annular, it will be seen that the 

 annulus is very narrow in this part of its path — including 

 its passage across Abyssinia. At Aden, there will be a 

 very large eclipse, beginning at loh. 23m. A.M., local mean 

 time, and ending at 2h. im. p.m. ; at greatest phase about 

 oh. 12m., the magnitude will be 0*97 of the sun's dia- 

 meter. The difference between the illumination of the 

 sky while any portion, no matter how small, of the direct 

 light of the sun remains, and the instant it is entirely 

 extinguished in a total eclipse, is so great as we know 

 from our experience of total eclipses, that there may 

 probably be a doubt as to the possibility of utilising the 

 eclipse in question, in a further endeavour to observe the 

 intra-mercurial planet or planets discovered by Prof. 

 Watson. The next total eclipse of the sun will take 

 place on January 1 1, 1880, and although, notwithstanding 

 the long track of the shadow across the Pacific Ocean, it 

 may be possible to secure observations, the interval 

 available for so doing cannot be more than half that at 

 the command of observers during the eclipse which 

 traversed the United States last July. 



Comets of Short Period.— An ephemeris of Bror- 

 sen's comet, which, according to the calculations of Prof. 

 Schulze, will arrive at perihelion on March 30, 1 879, will be 

 found in Asiron. Nach., No. 2,220 ; as already stated in 

 this column, it is likely that the comet will be first ob- 

 served at the southern observatories. About six weeks 

 later Tempel's comet, 1867 n, which was re-observed in 

 1873, after undergoing great perturbation from the planet 

 Jupiter, will be due at perihelion ; the elements deduced 

 from the observations of 1873 alone, by Dr. Sandberg, 

 would assign, without taking account of perturbation,, 

 April 26 for the perihelion passage, but according to an 

 orbit just published by M. Raoul Gautier, of Geneva 

 which he says may be considered the most probable one 

 till the observations to be expected next year, afford 

 additional means of determining the mean motion, the 

 comet would not be in perihelion till May 8, in which 

 case its apparent track in the heavens will differ little 

 from that which it pursued in 1873, when it arrived at 

 its least distance from the sun on May 9. It is pretty 

 sure to be always a faint object except for the larger 

 telescopes, and considering the uncertainty which still 

 appears to exist regarding the mean motion at its last 

 appearance, a close search may be necessary for its re- 

 discovery. M. Gautier is calculating the effect of Jupi- 

 ter's attraction during the actual revolution, with the 

 intention of pubHshing an ephemeris in due time ; this 

 effect, however, must be small, as the comet has not 

 been nearer to the planet than about i'$ during the 

 interval. The ensuing ■ return of Faye's comet in the 

 latter part of the year 1880 will take place under much 

 more favourable circumstances for observation than has 

 been the case at any of its appearances since 1843, when 

 it was first detected by the French astronomer ; indeed, 

 in 1851, 1858, 1865-66, and 1873 it was always a faint 

 object, but the admirable calculations of Dr. Axel MoUer 

 have enabled us to follow its course with extreme pre- 

 cision, with a precision perhaps greater than has yet 

 attended similar investigation in the case of any other 

 comet during so long a period. Though the date of 

 perihelion passage is not yet exactly ascertained, the 

 comet will probably approach almost as near to the earth 

 as in the autumn of 1843, ^^^ will be observable for many 

 months. 



The Saturnian Satellite Mimas.— According to 

 elements which represent approximately the Washington 

 observations, 1 874-77, the foUowingwill be times of greatest 

 eastern elongation of Mimas : — 



h. h. 



November 18 at 8"i 

 19 „ 67 



November 15 at 12*3 



16 „ 109 



17 .. 9*5 

 At these times, on the assumption of circular motionj 



the distance of the satellite from the end of the ring would 

 be about 8 '. 



The Minor Planet Ismene. — According to a calcu- 

 lation of the elements of the small planet Ismene, No. 

 190, by Herr Leman, from observations between Sep- 

 tember 30 and October 31, it very closely approaches 

 Hilda., in its exceptionally great distance from the sun, 

 and consequent length of the period of revolution. We 

 have for comparison : — 



Ismene. Hilda. 



Mean distance 3'893 ••■ 3'9So 



Aphelion distance 4'466 ... 4"595 



Sidereal period in days ... 2'8o5 ... 2855 

 years ... 7-68 ... 7-85 



Another group is formed by Cybele, Freia, Sylviar, 

 Camilla, and Ilermioiie, wherein the periods vary from 

 2297 days to 2377, the mean distance for the group, 

 3*45 1. Eventually the planets which approach so near to 

 the orbit of Jupiter, as Ismene and Hilda, will furnish 

 independent determinations of his mass, though the 

 narrow limits of probable error, within which its valui 



