66 



NA TURE 



[May 21, 1908 



discusses 160 observations of the peculiar variable 

 RV Tauri (45, 1905). The light-curve of this object is of 

 the /3 L3ra2 type, and the maxima and secondary minima 

 present variations in amplitude which appear to be 

 irregular. Between November, 1904, and July, 1905, the 

 character of the variation seems to have altered completely, 

 while further observations made at the Laws Observatory 

 during 1906 and 1907 indicate that the curve has again 

 changed its form. This object then presents an unsolved 

 problem similar to that presented in the cases of R Sagittae 

 and V \'ulpeculae. 



Photometric Observ.'vtions of Short-period Varhele 

 Stars. — No. 4247 of the Asironomische Nachrichtcn 

 (p. 3b9, May 8) contains a series of results of the observa- 

 tions of twenty-nine variable stars of short period obtained 

 by Herr H. v. Zeipel at the Upsala Observatory during 

 1907. For each star two comparison stars were employed, 

 and their positions and magnitudes are given at the head 

 of each table. 



The Relative Accuracy of Variocs Double-star 

 Observers. — A short paper by Herr V. Ehrenfeucht, 

 appearing in No. 4247 of the Astrononiische Nachrichtcn 

 (p. 381, May 8), deals with the relative accuracy of the 

 principal double-star observers. The resulting figures were 

 obtained by comparing the measures of these observers 

 with the ephemerides of fifty-two well-known doubles, and 

 the probable errors in position-angle and distance are given 

 for eleven observers. The errors in distance range from 

 o".os5, for Schiaparelli, to o"-ioo, for Madler, the mean 

 value for all the observers considered being o"'698. 



Italian Observations of the Sun during 1907. — The 

 usual summary, by Prof. Ricc6, of the observations of 

 spots, faculjE, and prominences made at Catania during 

 last year, appears in No. 3, vol. xxxvii., of the Mcmorie 

 della Societa degU Spctlroscopisti Italiani. 



The present paper deals especially with the second 

 semestre of 1907, but the values for the whole year are 

 given. For the period July to December the mean daily 

 frequencies of spots, faculae, and prominences were 5.7, 

 2.1, and 4.7 respectively, whilst for the whole year the 

 corresponding values were 5-5, 3-4, and 4-3. 



The Natal Observatory. — Mr. Nevill's report of the 

 work done at the Natal Observatory during 1907 is, as 

 usual, chiefly devoted to the meteorological results obtained 

 at the various meteorological stations of the colon\". The 

 only astronomical note of general interest is that a series 

 of observations of comet i907d was made by Mr. A. E. 

 Hodgson, and the results are to be communicated to the 

 Royal Astronomical Society. The magnetic declination at 

 Durban for January i, 190S, is given as 22° 27' W., with 

 a yearly decrease of 12', and the present value of the dip 

 is 63°. 2. 



Solar Phenomena and Terrestrial Temperatures. — In 



a paper published in the Bulletin de la Socifti astronoinique 

 dc France for May, Dr. J. Loisel discusses the relation- 

 ships between the activity of various solar phenomena and 

 the amount of heat received at the earth's surface. The 

 results are based on the observations made at Montpellier 

 during the period 1883-1901, and are of such interest as to 

 suggest the desirability of prosecuting this research in 

 many more different localities. Plotting the actinomctric 

 results obtained at Montpellier, together with the frequency 

 curves for sun-spots, facula?, and prominences. Dr. Loisel 

 shows that they are distinctly analogous, but the terrestrial 

 variation is an inversion of the solar variations. 



THE OKAPI MONOGRAPH.' 



OllORTLY after the arrival in London of the first com- 

 plete skin of the okapi, the administration of the 

 Congo Free State at Brussels sent urgent orders to its 

 officials on the L'ganda border to procure other skins, and 

 also skeletons, of the then newly discovered animal. In 

 due course these orders were carried out, and a repre- 

 sentative series of specimens received at the Museum of 

 the Free State at Tervueren, a few miles out of Brussels, 



1 "Contribution a la Faune du Coneo." Vol. i., Okaoia. By Jnlien 

 Fraipont. Pp. 118; 38 plates. Amtnles du Miisee tin Congo, Zoolo^ie, 

 ;«r. 2. (Brussels, 1907.) 



some of which were mounted for public exhibition, while 

 others were reserved for study. With commendable 

 promptitude, the administration thereupon took steps to 

 arrange for a monograph of the okapi, the preparation of 

 which was entrusted in 1902 to Dr. F'orsyth Major, who 

 had already made a special study of the giraffe group. 



During the same year, that gentleman visited Belgium 

 for the purpose of studying the Tervueren specimens, upon 

 which he published several preliminary notes in La 

 Belgique Coloniale. Coloured and other plates for the 

 monograph were also prepared under his direction. Never- 

 theless, after something like two years' delay, no .MS. 

 was forthcoming, and the Secretary of the Free State felt 

 himself compelled to seek another author. Accordingly, 

 Prof. Julien Fraipont was approached, who, after some 

 demur, eventually consented, at the close of 1905, to under- 

 take the work, and to use, so far as practicable, the plates 

 prepared under Dr. Major's direction. 



The result of these negotiations is the present elaborate 

 and richly illustrated monograph, which bears on every 

 page testimony to the author's diligence and industry. In 

 one respect the delay has been of very considerable 

 advantage, since it has admitted of the examination and 

 comparison of a much larger series of specimens than was 

 available in 1902-3. Most of these, it should be men- 

 tioned, originally belonged to the authorities of the Free 

 State, by whom examples have been presented to the 

 museums of Stockholm, Lisbon, Paris. Madrid, and Ant- 

 werp. Altogether, the author had at his disposal no fewer 

 than a dozen skins, seven skeletons, and eleven skulls. 

 With such full material, the monograph could scarcely 

 fail to be otherwise than in a great degree exhaustive. 



Following the usual rule, the monograph opens with a 

 historical sketch of the discovery of the okapi and the 

 subsequent acquisition of fuller knowledge of its structure 

 and affinities. In the course of this chapter the author 

 discusses the identification of the okapi with " Set- 

 Typhon " of the ancient Egyptian frescoes and sculptures — 

 an identification which he refuses to admit. The idea is, 

 however, by no means dead, a special work on the subject 

 having been published in Paris last year. 



The next chapter is devoted to the general external 

 form and colouring of the creature, in the course of which 

 the author expresses his opinion that, if we except the 

 zebra-like pattern on the limbs and the general brilliance 

 of tone (rather a large order, by the way), the coloration 

 is not unlike that of many antelopes. Of great interest 

 are a number of figures of the limbs of different in- 

 dividuals to display individual variation in the matter of 

 colour-pattern. The skeleton forms the subject of the 

 following chapter, in the course of which the author 

 devotes particular attention to the nature of the horns of 

 the giraffe and okapi, and their correspondence with those 

 of other ruminants. The " vellericorn," or skin-covered, 

 tvpe presented by the former is evidently the most primi- 

 tive, and there can be equally little doubt that the cap 

 of bare bone at the tip of the okapi "s horn represents the 

 deer's antler. .\ further inference from the latter identifi- 

 cation is that the shedding of the antlers in deer is an 

 acquired character, and it is noteworthy that some Tertiary 

 stags seem to have piermanent antlers, while in several 

 of the less specialised living species, such as the Indian 

 sambar, the shedding does not take place annually. Front 

 views of a male and a female skull are given, although 

 little is said with regard to individual variation in skull- 

 width, of which we believe thefe is a good deal. In 

 mentioning the existence of a double bicipital groove to 

 the humerus, the author scarcely gives sufficient emphasis 

 to the fact that this feature is absolutely distinctive of the 

 Giraffida;. 



With regard to the habits of the okapi. Prof. Fraipont 

 has, of course, nothing new to relate, but the photographs 

 he gives of the equatorial forest seem to confirm the 

 suggestion that the striping of the limbs and hind-quarters 

 serves the purpose of breaking up the outline of the creature 

 in the comparativelv clear basal zone of the forest. 

 Copious extracts are given from the writings of those who 

 have obtained more or less nearly accurate information 

 with regard to the okapi 's haunts and mode of life. 



A casual survey of the four coloured plates included 

 among the illustrations will probably lead to the belief 



NO. 2012, VOL. 78] 



