18 



KNOWLEDGE 



[January 2, 1893. 



having but eighteen teeth, but its most marked peculiarity is 

 to be found in the circumstance that the single pair of front 

 or incisor teeth in each jaw have chisel-shaped crowns like 

 those of rats and beavers, and grow continuously through- 

 out the life of their owner. Another peculiarity occurs in 

 the extremely long and attenuated third finger of the 

 hand, which surpasses all the others in length, although 

 the whole hand is remarkably elongated. It also differs 

 from other lemurs in that all the toes of the foot, with the 

 exception of the first, have pointed claws, and thus 

 resemble the second toe of the ordinary kinds. In size 

 the aye-aye may be compared to a cat, and it has a 

 rounded and somewhat cat-like head, with a short face, 

 and large naked ears. The tail is long and bushy, and the 

 general colour of the fur dark brown. 



The aye-aye represents the extreme development of the 

 lemur type, and it is evident that its peculiarities of struc- 

 ture are correlated with equally well-marked traits of habit. 

 Unfortimately, however, from the nocturnal habits and 

 rarity of the creature itself, as well as from the absence of 

 a sufficient number of competent observers in its native 

 haunts, we are by no means so well acquainted with the 

 habits of this strange creature as is desirable. It appears, 

 however, that the aye-ayes live either in pairs or alone in 

 the bamboo forests of Madagascar, and that they are in the 

 habit of constrnctmg ball-like nests of leaves placed in the 

 forks of trees, to which they retire for their diurnal slumber. 

 The strong incisor teeth are certainly used for ripping up 

 the hard external cases of the sugar-canes, on which these 

 animals delight to feed ; and it is said that they are like- 

 wise employed to tear away the bark and wood from the 

 trunks of trees, and thus expose the burrows of wood- 

 eating larviT!, which are then extracted by the aid of the 

 thin middle finger. If any of our readers who may have 

 friends living in Madagascar can induce them to try and 

 obtain more particulars in regard to the aye-aye, they will 

 be confen-ing a real benefit on science. 



THE FACE OF THE SKY FOR JANUARY. 



By Hekbert S.\dler, F.R.A.S. 



SOLAR spots and faculse show no diminution in 

 number. The following are conveniently observable 

 minima of two Algol-type variables : — Algol, 

 .January 8th, lOh. 3.5m. p.m.; -January Uth, 7h. 

 2-im. P.M. ; January 14th, 4h. 13m. p.m. ; January 

 2yth, Oh. 17m. a.m. ; January 31st, 9h. Om. p.m. 

 U Cephei, January 3rd, 7h. 17m. p.m. ; January 8th, 6h. 

 57m. P.M. ; January 13th, Oh. 37m. p.m. ; January 18th, 

 6h. 10m. P..M. ; January 23rd, 5h. 56m. p.m. ; January 

 28th, 5h. 30iu. p.m. A maximum of the beautiful red 

 variable U Orionis is due on the 10th. 



Mercury is a morning star throughout the month, but 

 owing to his great southern declination he will be liable 

 to be obscured by mists near the horizon. He rises on the 

 1st at Gh. 18m. a.m., or Ih. 50m. before the Sun, with a 

 southern declination of 21 23', and an apparent diameter 

 of (ii", fijjjths of the disc being illuminated. On the 7th 

 he rises at Oh. 31m. a.m., or Ih. 33m. Ijefore the Sun, with 

 a southern declination of 22" 37', and iin apparent diameter 

 of 51", iVn'^s of the disc being illuminated. On the 12th- 

 lie rises at 6h. tOm. a.m.. or Ih. 18m. before the Hun, with 

 a southern declination of 23'' 19', and an apparent diameter 

 of 5-^", j^ffyths of the disc being illuminated. On the 17th 

 lie rises at 71i. a.m., or Ih. before the Sun, with a .southern 

 declination of 23° 31', and an apparent diameter of 5V', 

 •ji/gths of the disc being illuminated. After this he 

 approaches the Sun too closely to be observed. He is at 



his greatest western elongation (22|°) on the 1st. During 

 the time he is visible he passes from Ophiuchus into 

 Sagittarius, without approaching any very conspicuous star. 



Venus is a morning star, but is rapidly decreasing in 

 brightness. She rises on the 1st at 5h. 4Cm. a.m., or 2h. 

 22m. before the Sun, with a southern declination of 

 21° 10', and an apparent diameter of llf", tVo'^^ of the 

 disc being illuminated, and her brightness being about what 

 it was at the end of last January. On the 12th she rises 

 at Oh. 13m. a.m., or Ih. 51m. before the Sun, with a 

 southern declination of 22° 40', and an apparent diameter 

 of IIV', i%%ths of the disc being illuminated. On the 

 31st she rises at 6h. 38m. a.m., or Ih. 5m. before the Sun, 

 with a souihern declination of 22° 0", and an apparent 

 diameter of lOJ", xbo^'l^s of the disc being illuminated. 

 During the month she passes through Ophiuchus into 

 Sagittarius, but without approaching any conspicuous star 

 very closely. 



Mars is still visible in the evening, but is now getting a 

 very insignificant object in size, and rapidly decreasing in 

 brightness. On the 1st he sets at lib. 34m. p.m., with a 

 northern declination of 1° 2', and an apparent diameter of 

 7-6". He is still markedly gibbous. On the 15th he sets 

 at lib. 30m. p.m., with a northern declination of 5° 0', 

 and an apparent diameter of 7'1". On the 31st he sets 

 at lib. 31m. p.m., with a northern declination of 9° 14', 

 and an apparent diameter of 6^". He describes a direct 

 path through Pisces during the month. On the evening 

 of New Year's Day he is about 3' north of the 6-4 magnitude 

 star LI 201. At about 5h. 40m. p.m. on the 14th he will 

 probably occult the 0th magnitude star LI 1299. 



Jupiter is still the most conspicuous object in the evening 

 sky. On the 1st he sets at Oh. 47m. a.m., with a northern 

 declination of 5° 4', and an ajsparent equatorial diameter of 

 40|". On the 31st he sets at lib. 6m. p.m., with a northern 

 declination of 0° 33', and an apparent equatorial diameter 

 of 37". During the month he describes a short direct path 

 in Pisces. On the evening of the 8th he will be 

 about ^° north of the 5^ magnitude star 80 Piscium. 

 On the 23rd he will be occulted by the Moon, but the 

 phenomenon will not be visible in these latitudes. The 

 following phenomena of the satellites occur while Jupiter 

 is more than 8° above and the Sun 8° below the 

 horizon. On the 1st a transit ingress of the third 

 satellite at 8h. 39m. p.m., and its egress at lib. 7m. p.m. 

 On the 3rd a transit ingress of the first satellite at 9h. 

 2m. P.M. ; of its shadow at lOh. 23m. p.m. ; and a transit 

 egress of the satellite at lib. 10m. p.m. On the 4th an 

 occultation disappearance of the first satellite at Gh. 22m. 

 p.m., and its reappearance from eclipse at 9h. 54m. 15s. 

 P.M. On the 5th a transit egress of the first satellite at 

 5h. 45m. P.M. ; of its shadow at 7h. 5m. p.m. ; and an 

 occultation disappearance of the second satellite at 9h. 

 30m. P.M. ' On the Gtb an eclipse reappearance of the third 

 satellite at Oh. 9m. 53s. p.m. On the 7th a transit egress of 

 the second satellite at 7h. 13m. p.m. ; a transit ingress of its 

 shadow at 7h. 23m. p.m., and a transit egress of tlie 

 shadow at 9h. 51iii. p.m. On the lOtli a transit ingress of 

 the first satellite at lOli. 58m. p.m. On the 11th an 

 occultation disappearance of the first satellite at 8li. iKm. 

 P.M. On the 12th a transit ingress of the first sateUite at 

 5h. 27m. P.M.; of its shadow at Oh. 48m. p.m. ; a tran^jit 

 egress of the satellite at 7li. 41m. p.m., and its shadow at 

 Oh. Im. P.M. On the 13th an eclipse reappearance of the 

 first satellite at Oh. 18m. 58s. p.m. ; an eclipse disappear- 

 ance of the third satellite at 8h. 23m. 13s. p.m., and its 

 reapijearanee at lOh. 11m. 39s. p.m. On the 14th a 

 transit ingress of the second satellite at 7h. 18m. p.m. ; 

 its egress at 9h. 52m. p.m. ; and the transit ingress of its 



