November io, 1892] 



NATURE 



39 



A CAPITAL annotated catalogue of the mammals collected by 

 Dr. W. L. Abbott in the Kilima-Njaro region, East Africa, has 

 been prepared by Mr. F. W. True, and printed in the Pro- 

 jeedings of the fifteenth volume of the U.S. National Museum, 

 vith several plates. Dr. Abbott has presented to the National 

 Museum many African collections ; but none of them, according 

 .0 Mr. True, is of more interest than the collection of mammals. 

 The specimens have been prepared with much care, the skins 

 being almost invariably accompanied by the skulls and furnished 

 vith labels giving the locality and date of capture, sex, and 

 ther data. In determining the species Mr. True has found it 

 lecessary to depend almost exclusively on the literature, on 

 account of the lack of specimens for comparison, but the identi- 

 ! cations have been made with much care, and may, he thinks, 

 n the whole, be relied upon. Several species apparently new 

 • re represented in the collection : Dendrohyrax validus, Jl/us 

 iiiilus, Dcndromys nigrifrons, Scuirus undulattis, Cephalophus 

 padix. On one who has studied the North American mam- 

 joalian fauna in detail, Mr. True says, the thought impresses 

 itself that the condition of species, as regards variation, is 

 different in the Ethiopian and Nearctic regions. In North 

 America individual variation seems far less extensive than in 

 Africa, while geographical variation appears to be more exten- 

 sive and constant. In Dr. Abbott's collection great individual 

 variation is especially apparent in the genera Galago, Genetta, 

 and Canis. It is true that the species of the last-named genus 

 everywhere present much individual variation, but in North 

 America its chief variations appear to be geographical in 

 character. The known range of several species is considerably 

 extended by Dr. Abbott's labours. 



An important contribution to spectroscopy appears in No. lo 

 of Wiedemann's Annalen in the shape of a paper on the infra- 

 red emission spectrum of the alkali metals, by Benjamin W. 

 Snow. The method is distinguished by the adoption of a modi- 

 fied form of the bolometer and a very delicate galvanometer 

 with quartz fibre suspension. The fibre, supplied by Prof. 

 Boys, was 40 cm. long. With a scale at a distance of 3tn., a 

 deflection of imm. corresponded to a current of 1*5 x 10"'^ amp. 

 The spectra were obtained by means of a silicate-flint prism, so 

 as to avoid the overlapping of the infra-red spectra which seems 

 to be inevitable where gratings are used. Since no infra-red 

 lines could be traced in the spectrum produced in the Bunsen or 

 the oxy-hydrogen flame, the electric arc was used, the current 

 being derived from the very uniform Berlin Central supply. The 

 best arrangement for the arc was found to be a hole bored through 

 the centre of the carbon, containing a "wick" of the com- 

 pressed salt. The bolometer consisted of two platinum-thread 

 resistances, A platinum wire embedded in silver was ham- 

 mered flat, so as to have a breadth of o'CSmm. and a thickness 

 of 000036mm. Two such threads were fastened side by side 

 with shellac on a mica frame. One of them was blackened in 

 a turpentine flame and exposed to the light, the other being 

 covered. The difference of resistance produced by the incident 

 rays was measured by a Wheatstone bridge arrangement, with 

 a shunt contrivance for enlarging the scale of the bridge wire. 

 The resistance of each of the platinum ribbons under ordinary 

 conditions was 75 ohms. The other branches of the bridge were 

 made of German silver wire. The slit of the spectrometer was 

 adjusted to o'imm., corresponding to an angle of i"68 minutes 

 of arc in the spectrum, whilst the breadth of the platinum thread 

 corresponded to an arc of i'-6. The current through the bridge 

 was maintained at one-fortieth ampere. In the measurement of 

 the intensity of the lines, the energy of radiation was taken as 

 proportional to the first throw. It was found that a standard 

 candle at im. distance gave a throw of 150mm. A preliminary 

 investigation of the carbon spectrum revealed a large number of 

 NO. 1202, VOL. 47] 



bands reaching up to \ 20620, the principal less refrangible 

 bands being between 



7000 and 7700 

 7850 and 8600 

 90CO and 1 0000 

 10750 and I I 600 

 13700 and 15000 

 These were made up of innumerable fine lines. It was'also ob- 

 served that the carbon spectrum vanished in comparison with 

 the metallic spectrum as soon as the latter was brought into 

 [ play. Of the five metals investigated, viz., sodium, potassium, 

 rubidium, lithium, and cassium, the two rarest were found to be 

 I specially rich in infra-red lines. Sodium showed maxima at 

 1 8i8d, 1 1270, 12400, and 18360, potassium at 7670, 10820, 

 1 11580, 12250, and 14610, lithium at 8070, rubidium at 7910, 

 } 9980, 13120, and 14760, and caesium at 8380, a large one at 

 , 8820, and others at 9980, 13270, and 14530. Kayser and 

 Runge's empirical law for the alkalies was confirmed for the infra- 

 red of lithium and sodium, but not for the other three metals. 



Mr. Elliott Coues, of the Smithsonian Institution, defends 

 in Science the rule, in biological nomenclature, "once a 

 synonym, always a synonym," for the form of which he believes 

 himself to be in some degree responsible. He illustrates the 

 real meaning of the aphorism in the following way. Let there 

 be a genus Smithia in botany. Let a genus Jonesia then be 

 named. Let /onesia then be found to be the same genus as 

 Smithia. Then the n&me Jonesia "lapses into jsynonomy," 

 and cannot be thereafter applied to any other genus in botany. 

 That is all that is meant by the saying "once a synonym 

 always a synonym." In other words, ii Jonesia is not good for 

 what it originally meant, it is good for nothing ; it is to be 

 deleted absolutely, and cannot come into re-existence by transfer 

 to any other genus. Mr. Coues shows that the same principle 

 holds for all specific names within their respective genera. 

 Example : Let there be a Rosa Smithi. Let some one then 

 name a Rosa Jonesi. Let R. [onesi be considered to be the 

 same species as R. Smithi. Then there can never be a R. 

 Jonesi ; that is to say, no other species of Rosa can be specified 

 as Jonesi. But, of course, if any one discovers, after this 

 reduction of Jonesi to a synonym of Smithi, that what had 

 been called R. Jonesi \% a good species, \\i&n Jonesi revives as 

 the name of that species ; and the fact that it had been 

 (erroneously) regarded as a synonym of Smithi is no bar to its 

 use in its original sense. 



The Geological Survey of America has published a paper, 

 by Mr. J. S. Diller, on the Geology of the Taylorville region in 

 the Sierra Nevada, California, immediately north of the fortieth 

 parallel. In this region there are eighteen sedimentary forma- 

 tions and seventeen eruptive masses. The former have a total 

 thickness of 24,500 feet; 17,500 feet are probably Palaeozoic, 

 and 7000 feet are Mesozoic. Among the sedimentary rocks, 

 one horizon in the Silurian, two in the Carboniferous, three or 

 more in the Trias, and five in the Jura have been definitely 

 recognized by fossils. Among the eruptives there is great 

 variety. Their extravasation, beginning early in the Palaeozoic, 

 recurred vigorously in the Triassic and at the close of the 

 Jurassic, and, finally, also in the Neocene and Pleistocene. The 

 dioritic rocks of the region are a portion of the great granitoid 

 mass of the upper Sierra Nevada, and are evidently eruptive, 

 with well-defined contact phenomena in Triassic formations. 

 Their eruption is certainly post-Triassic, and may have taken 

 place immediately at its close or after the deposition of the 

 Jurassic. There are at least four unconformities fn the geologic 

 column of the Taylorville region. During the greater part, if 

 not the whole, of the Palaeozoic, the sea covered the region 

 now occupied by the northern portion of the Sierra Nevada. 

 The great disturbance at the close of the Carboniferous may 



