68 



NATURE 



[May 27, 1875 



submitted them to very complete discussion, the results 

 of which he has just made known. His inferences are 

 generally opposed to those drawn by Klinkerfues and 

 Oppolzer. With one of the systems of elements given 

 by the latter, he calculates the apparent path of the 

 comet from Nov. 30 to Dec. 8, finding, as was to be 

 expected, a good agreement with Pogson's observations, 

 and with the rate of motion in R.A. given by his com- 

 parisons on the first morning, that of Dec, 3, but the 

 ephemeris does not agree with the rate of motion on the 

 following morning, which, Pogson's differences are sufficient 

 to prove, had not diminished. And it should here be ob- 

 served that the differences of R. A. were evidently obtained 

 with considerable precision, as might be looked for from 

 so practised an observer as Mr. Pogson. The orbit here 

 referred to is as follows :— Mean anomaly, Dec. 3*0 

 Berlin time, - 5° 6'-8 ; longitude of perihehon, 141° 9' ; 

 ascending node, 244° 34' ; inclination, 10° 28' ; angle of 

 excentricity, 54° 17', the semi-axis major being that 

 assigned by Michez for Biela's Comet, and corresponding 

 to a mean daily motion of 53o"-i. Again, Bruhns ob- 

 serves that it speaks further against the identity, that by 

 all the ephemerides, at least from Nov. 23 to Dec. 3, the 

 first days in the northern and later in the southern hemi- 

 sphere the comet should have been more conspicuous 

 than at the time of Pogson's observations, and it is 

 unlikely that it would have escaped notice, particularly in 

 the northern hemisphere. He so far agrees with Oppolzer, 

 that no assumed date for perihelion passage will bring 

 about an agreement of places calculated from the elements 

 of Biela, with those observed ; and that an extension of 

 the comet's period of revolution to 2528 days, without a 

 near approach to the planet Jupiter, is most improbable. 

 In Oppolzer's orbit given above, the inclination is 10° 28', 

 while that deduced by Michez is 12° 22'; and to prove that 

 such diminution is not to be accounted for by perturba- 

 tion during the assumed near approach of Biela to the 

 earth about the time of the meteor-shower, he has calcu- 

 lated the effect of the earth upon the elements of Biela, 

 with the perihelion passage fixed to Dec. 2775, ^^^ epoch 

 which would occasion the nearest approach of the two 

 bodies. The incUnation of the orbit to the ecliptic is 

 found to be increased i'-6 only, the node is advanced o'-4, 

 the perihelion longitude 7'"3, and the angle of excentricity 

 is diminished I'S. The earth's perturbations during such 

 a near approach as is possible in the orbit of Biela (for 

 1866) would not therefore account for a change of ele- 

 ments sufficient to represent the places of Pogson's Comet. 

 Bruhns then makes two assumptions with regard to the 

 ratio of the curtate distances of the comet from the earth 

 at the times of the Madras observations on Dec. 3 and 4, 

 and in both cases arrives at retrograde orbits : the motion 

 of Biela's Comet is dh-ect. The first of these orbits from 

 which he computes an ephemeris is as follows (we adapt 

 the longitude of perihelion and the inclination to the 

 catalogue form of expressing them) : — Perihelion passage 

 1872, Dec. 15*3763 Greenwich time; longitude of peri- 

 helion, 332° 28' ; ascending node, 33° 1 1' ; inclination, 

 31° 13' ; perihelion distance, 0-035205, Hence the track 

 of the comet would be— 



We believe there is little doubt that, so far as can be 

 ascertained from Pogson's two days' positions and the 

 rate of motion indicated by his comparisons, the orbit of 

 the comet observed by him was retrograde, and therefore 

 agree with the inference of Prof. Bruhns that it had no 

 relation to Biela's Comet, or, we may add, to the magni- 



ficent meteoric display of 1872, Nov, 27, notwithstanding 

 the singularity of its discovery by Pogson, in consequence 

 of the telegram sent to him by Klinkerfues, which was 

 grounded on the opposite opinion. 



LECTURES AT THE ZOOLOGICAL 



GARDENS* 



IV. 



May 13. — Mr. Garrod on Antelopes and their Allies 



THE true Ruminant Animals characterised among 

 Artiodactylate Ungulata by the absence of incisor 

 teeth in the upper jaw, as well as by the possession of a 

 stomach in which three separate compartments, named 

 paunch, honeycomb bag, and reed, are always present,f 

 naturally fall into three different families, the Chevrotains, 

 the Deer, and the Antelopes. The first and last of these 

 remain for consideration. 



In the Antilopine, or Cavicorn section, as the latter 

 name implies, the horns are hollow organs. They are 

 epidermic in structure, being composed of hairs aggluti- 

 nated together to form tubes, which are moulded and 

 fixed upon osseous protuberances of the frontal bones. 

 These " horn cores " are quite different in their nature 

 from the antlers of the deer tribe, as they persist through- 

 out the life of the individual, and are perfectly continuous 

 in their structure with the bones from which they spring. 

 The horns themselves bear much the same relation to 

 the thin layer of vascular membrane which covers the 

 " cores " that the nails on the fingers do to the subjacent 

 soft parts ; in the Rhinoceros the horn or horns, though 

 similar in structure, are solid throughout. In many 

 species the horns are present in both sexes, and in one 

 genus ( Tetraceros) there are two pairs, one attached near 

 the anterior and the other near the posterior margin of 

 the frontal bones. 



Many attempts have been made to classify these animals 

 by means of the peculiar structures which are found in 

 some species and not in others. Among the most im- 

 portant of these are the condition of the muffle, or tip of 

 the nose, which is moist in some, as in the ox, and hairy 

 in others, as the sheep. The gland below the eye is also 

 a varying feature, being largely developed in the Indian 

 Antelope, for example, and absent in the Eland. In most 

 species there are two small " false hoofs," remnants of the 

 second and fifth digits, behind the true foot. These, how- 

 ever, are absent in the Royal Antelope and the Pallah. 

 Whether the horns are cylindrical, as in the Chamois, or 

 grooved, as in the Koodo ; straight, as in the Oryx, 

 arched, as in the Ibex, or spiral, as in the Markhour ; 

 smooth, as in the ox, or transversely ringed as in most, 

 are also tangible characters, by the combination of which 

 with others of less significance various endeavours have 

 been made to arrange the family. These, nevertheless, 

 are none of them satisfactory, on account of the large 

 number of the possible combinations which are to be 

 actually found, at the same time that the relative import- 

 ance of the different included characters is scarcely capable 

 of being estimated. 



There are two animals, the Giraffe of Africa and the 

 Pronghorn, or Cabrit, of the western regions of North 

 America, which are evidently closely allied to the Ante- 

 lopes, and are probably nothing more than extreme modi- 

 fications of them. In both, the horn processes cr horns 

 are developed in both sexes, at the same time that neither 

 possess false hoofs. The abnormal feature in the Giraffe 

 is found in the horn-like developments, which are pedestals 

 of bone, covered with the ordinary skin of the body, 

 and capped with a tuft of hair. These pedestals, how- 

 ever, differ very materially from those in the Muntjacs 

 among the Deer, and from the horn-cores of the typical 



* Continued from p. 28. 



t A fourth, the manyplies, is found in all but the Chevrotains. 



