40 



NATURE 



[November io, 1892 



have been accompanied by an uplift, forming land during the 

 early Triassic ; but if so, it subsided and was ready to receive 

 the deposits of the upper Triassic. The disturbance at the 

 close of the Triassic formed no land in the northern Sierra 

 region, but that which closed he Jurassic was accompanied 

 by a great upheaval, excluding the sea to the western base of 

 the Sierras. The general structure of the Tsylorville region 

 involves a synclinal and two limiting anticlinals. After the 

 folds were overturned toward the north-east, the Grizzly anti- 

 clinal was affected by an overthrust fault in the same direc- 

 tion. The throw along this fault in the older strata is so much 

 greater than in those of Jurassic age as to suggest that a large 

 part of the displacement took place at the close of the 

 Triassic, and was followed by movement on the same plane at 

 the close of the Jurassic. 



Mr, Stanford has issued an interesting and valuable contoured 

 map of the county of London. The scale is three inches to a mile. 

 The contour lines or lines of equal altitude are drawn at 25 feet 

 intervals. The lowest contour is 25 feet above the level of the 

 sea, ordnance datum, which is X2 feet 6 inches below Trinity 

 high water. The whole of the alluvial flat lying below the low- 

 est contour, or at a less altitude than 12 feet 6 inches above the 

 river Thames (Trinity high-water mark), is covered by a dark 

 brown tint. 



The third volume of reports upon the fauna of Liverpool 

 Bay and the neighbouring seas has been issued. The reports 

 have been written by members of the Liverpool Marine Biology 

 committee and other naturalists, and edited by Prof. W. A. 

 Herdman, F.R.S. 



Messrs. Gurney and Jackson have published the 

 Zoological Record {ox \%<^\ . It is the twenty-eighth volume of 

 the series. Mr. D. Sharp, F.R.S., has acted as editor, and has 

 had the co-operation of many able zoologists. It is intended 

 that in future the volume shall be published in August or 

 September. 



Photographers will read with great interest an admirable 

 paper by Captain Abney, in the November number of the 

 Journal of the Camera Club, on "shutters," which he describes 

 as " a piece of apparatus which is the very joy and toy of the 

 photographer's existence." The paper is fully illustrated. 



The Rev. L. A. Walker sends to the current number of the 

 Entomologist some statistics of the entomology of the Hague, 

 where he acted as chaplain during July. The entomology of 

 Holland seemed to him very disappointing in number of species, 

 and also in individuals in the great majority of cases ; less 

 productive, in fact, than the ordinary run of country places 

 at home. 



At the meeting of the Linnean Society of New South Wales 

 on September 28, Mr. R. Etheridge, junior, exhibited seeds of 

 the "Bean-tree," possibly an Erythrina, from Macdonald 

 ranges. Central Australia. The seeds are strung and used as 

 necklaces by the aborigines, who use the wood of the same tree 

 for producing fire by friction, and also for shields, on account of 

 its lightness. 



A compound of gold and cadmium of the composition 

 AuCd has been isolated by Messrs. Heycock and Neville, and 

 is described by them in the November number of the Journal 

 of the Chemical Society. During the course of a series of 

 experiments last year upon solutions of gold and cadmium in 

 melted tin, it was observed that the amount of lowering of the 

 freezing-point of the tin by the simultaneous introduction of gold 

 and cadmium was considerably less than the sum of the effects 

 which each of the two latter metals would produce alone. It 

 was surmised that this difference must be due to combination 

 between the gold and the cadmium. Moreover, the product o 

 this combination appeared to be only sparingly soluble in tin, 

 NO. 1202, VOL. 47] 



for a considerable quantity of a crystalline precipitate was pro- 

 duced, but owing to the difficulty of freeing it from the tin which 

 solidified over it upon removal, the compound was not obtained 

 in a state of sufficient purity to enable a definite conclusion con- 

 cerning its composition to be arrived at. Messrs. Heycock and 

 Neville now announce that they have succeeded in preparing 

 the compound in an entirely different manner, and in isolating it 

 in a state of comparative purity. The following is the best 

 mode of procedure : — A piece of the hardest combustion tubing 

 is sealed at one end and slightly bent in the middle so as to form 

 a V-tube of very large angle. A quantity of pure gold is placed 

 in the sealed limb, together with three or four times its equivalent 

 of cadmium. The open end is then drawn off so as to enable 

 the tube to be exhausted by means of the Sprengel pump. As 

 high a vacuum as possible should be obtained, and the tube 

 subsequently sealed. The apparatus is then arranged upon 

 a combustion furnace in such a manner that the excess of 

 cadmium when liquefied may run away from the alloy. When 

 the cadmium first melts it is advisable to vigorously shake the 

 tube so as to diffuse the gold well among the cadmium. The 

 combination then occurs suddenly, accompanied by bright 

 incandescence of the gold. When the larger excess of cadmium 

 has been allowed to run away from the compound, the end of the 

 tube containing the latter is heated for about five hours to a 

 temperature about that of the softening of glass, when the 

 remainder of the excess of cadmium distils regularly off, until 

 towards the expiration of the five hours no further condensation 

 occurs. The product thus left behind was found in thiee 

 successive experiments to contain about 637 per cent, of gold, 

 the percentage required for a compound of the composition 

 AuCd. The compound of gold and cadmium thus obtained 

 presents a silvery greyish-white appearance, is very brittle, and 

 exhibits a crystalline fracture. The action of acids upon it is- 

 somewhat singular. Cold acids appear to be without material 

 action upon it, but hot nitric or hydrochloric acid attacks it with 

 great energy, the cadmium passing into solution and the gold 

 being left in the shape of the original ingot. 



The additions to the Zoological Society's Gardens during the 

 past week include a Purple-faced Monkey {Seinnopithecus leii- 

 coprymmis) from Ceylon, presented by Mrs. Elgee ; six Short- 

 tailed Voles [Arvicola agrestis) from Scotland, presented by Mr. 

 J. E. Harting, F.Z.S. ; two Laughing Kingfishers [Dacelo 

 gigantea) from Australia, presented by Mr. J. W. Hornsby ; a 

 Golden Eagle {Aquila chrysaetus) from Labrador, presented by 

 Mr. J. G. Baxter ; a Jackdaw (Corvus monedula) British, pre- 

 sented by the Rev. H. W. Reynolds ; three Geckos 



(^Gecko verlicillalus) from Burmah, presented by Mr. W. G. 

 Bligh; two American Darters {Plotus anhinga). & Common 

 Boa {Boa constrictor) from South America, four Bar-tailed 

 Pheasants {Phasianus reevesi i <J $ ? ) from China, purchased. 



OUR ASTRONOMICAL COLUMN. 



A bright Comet is announced in Andromeda, seventy 

 seconds preceding Struve 72. 



Comet Barnard (October 12).— The following is a con- 

 tinuation of the ephemeris we gave last week of Comet Barnard 

 taken from Astronomische Nachrichten, No, 3125. 



Ephemeris for I2h. Berlin M.T. 

 . R.A. Decl. Log r. Log A. Br. 



^29^- h. m. s. 



Nov. II... 20 46 49 ... -J-2 33*3 



12... 49 40 ... 2 157 



13... 52 32 ... I 58-3 ... o'2262 ... 0-1648 ... 0'97 



14... 55 25 ... I 41-2 



15... 20 58 19 ... I 24-4 



16... 21 I 14 ... I 79 



17.., 21 4 9 ... -fo 51-6 ... 0-2250 ... 0-I7I3 ... 094 



