No. 1072, Vol. 42] 



NA TURE 



67 



Rjninsula culminating in that of the Dorians, came from the 

 middle or lower Danube valley. Hence the importance of 

 prehistoric remains in Hungary for a knowledge of prehistoric 

 events in Central Europe. 



Another important paper is contributed by M. Moissan to 

 the current number of the Coniptes rcndtis upon carbon tetra- 

 fluoride, CF4. Five modes of preparing the gas are described, 

 together with several new properties which have been investigated 

 since the publication of the preliminary notice a few weeks ago. 

 When gaseous fluorine is allowed to enter a platinum tube filled 

 with marsh gas, CH4, a violent combination, accompanied by 

 incandescence, takes place, carbon being deposited and a mixture 

 of various fluorides including carbon tetrafluoride formed. Fluorine 

 also reacts somewhat violently with chloroform, CHCI3. When 

 the free element is led into cooled chloroform it is largely absorbed, 

 carbon tetrafluoride being again produced, and for the most part 

 remaining dissolved in the excess of chloroform. If the fluorine 

 is heated to 100^ before passing into the chloroform incandescence 

 occurs, a flame appears at the exit opening of the platinum ap- 

 paratus, carbon is again deposited, and the tetrafluoride largely 

 found in the gaseous product. Fluorine also expels chlorine from 

 tetrachloride of carbon, CCI4, for if it is led into a quantity of 

 the tetrachloride contained in a gently-warmed platinum flask, 

 the issuing gas is found to be a mixture of free chlorine and 

 carbon tetrafluoride. A large proportion of the latter gas 

 remains dissolved in the excess of carbon tetrachloride, and may 

 be readily- obtained fairiy pure by gently boiling the residual 

 liquid in a glass vessel and collecting the gas over mercury. As 

 described in our notice of the preliminary paper the lighter 

 varieties of amorphous carbon, such as wood charcoal and lamp 

 black, take fire in a stream of fluorine and continue burning as 

 long as combination occurs, the product consisting of several 

 gaseous fluorides, of which the tetrachloride is present in greatest 

 proportion. The method, however, by which carbon tetrafluoride 

 can be prepared most conveniently and in the purest form is as 

 follows. A quantity of silver fluoride, AgF, is placed in a 

 brass (J -tube fitted with two side tubes. Througli one of these 

 latter a stream of vapour of carbon tetrachloride is driven ; the 

 other serves as exit tube for the products of the reaction. The 

 apparatus is first filled with carbon tetrachloride vapour, the 

 portion containing the fluoride of silver is then heated to 195°- 

 220° C. and a steady stream of the tetrachloride maintained as 

 long as gas is evolved at the mercury trough. It is advisable to 

 add to the apparatus a small metallic spiral tube which can be 

 cooled to — 23° in order to condense any escaping vapour of the 

 tetrachloride, and which is so arranged that the condensed liquid 

 can be returned to the vessel in which the tetrachloride is being 

 vapourized and so passed again into the reaction tube. The last 

 traces of carbon tetrachloride may be removed by allowing the 

 gas to stand twenty-four hours over mercury in contact with a 

 few scraps of caoutchouc. In order to free it from admixed 

 heavier fluorides advantage is taken of the fact that large quanti- 

 ties of the tetrafluoride are absorbed by absolute alcohol. On 

 agitation with a little absolute alcohol, therefore, the tetrafluoride 

 is absorbed, and may be again liberated either by addition of 

 water, in which the gas is scarcely perceptibly soluble, or by 

 ebullition. If the latter plan is adopted the alcohol vapour may 

 be removed by washing through sulphuric acid. It is important 

 to use a metallic reaction tube in the preparation, inasmuch as 

 glass is rapidly attacked by carbon tetrafluoride, the product of 

 the reaction in a glass vessel consisting of a mixture of silicon 

 and carbon tetrafluorides, carbon dioxide, and a heavier fluoride 

 of carbon, CF4 -f- SiO, = CO., + SiF4. Carbon tetrafluoride 

 liquefiesat - 15° at the ordinary atmospheric pressure, and under 

 I a pressure of four atmospheres at 20°. When passed over heated 

 , sodium it is completely absorbed, carbon being deposited and 

 i sodium fluoride formed. Aqueous potash appears to be without 



action upon it, but alcoholic potash slowly absorbs it with 

 formation of carbonate and fluoride of potassium. 



The additions to the Zoological Society's Gardens during the 

 past week include a Blossom-headed Parrakeet {Palaornis cyano- 

 cephaltis <J),two Redeared Bulbuls {Pycnonotus jocosus) two 

 Red- vented Bulbuls {Pycnonotus hamorrhoiis), a Large Hill- 

 Mynah {Gracnla intermedia) from India, a Red-sided Eclectus 

 (Eclectus pectoralis ? ) from New Guinea ; two King Parrakeets 

 {Aprosmictus scapulatus d 9 ), a Pennant's Parrakeet {Platy- 

 cercus pennanti), a Chestnut-eared Finch (Amadina casianotis 

 9 ) from Australia, a Ceylonese Hanging Parrakeet {Loriculus 

 asiaticus) from Ceylon, a Mealy Amazon {Chrysotis farinosa), 

 two Yellow-shouldered Amazons {Chrysotis ochroptera), a Blue- 

 fronted Amazon {Chrysotis ccstiva), a Red-crested Cardinal 

 {Paroaria cucullata) from South America, a Levaillant's Amazon 

 {Chrysotis levaillanti) from Mexico, two Panama Amazons 

 ( Chrysotis panamensis) from Panama, a Yellow-vented Bulbul 

 [Pycnonotus crocorrhous) from Sumatra, two Orange-cheeked 

 Waxbills {Estrelda tnelpoda), two Red-bellied Waxbills {Estrelda 

 rubriventris), a Cut-throat Finch {Amadina fasciata d ), a 

 Shining Weaver Bird {Hypochera nitens), an Olive Weaver 

 Bird {Hyphantornis olivaceus) from South Africa, a Crimson- 

 crowned Weaver Bird {Euplectes fammiceps), a Grenadier 

 Weaver Bird {Euplectes oryx), a Green Glossy Starling {Lam- 

 procolius chalybeus) from West Africa, two Madagascar Weaver 

 Birds {Foudia madagascariensis cJ 9 ) from Madagascar, a Red- 

 headed Cardinal {Paroaria larvata) from Brazil, a Cardinal 

 Grosbeak {Cardinalis virginianus 9) from North America, 

 presented by Dr. Seton ; a Red-eared Bulbul (Pycnonottis 

 jocosus), a. Red-vented Bulbul {Pycnonotus hcemorr hous) from 

 India, presented by Lieut. -General Sir H. B. Lumsden, 

 K.C. S.I. ; a Ring-necked Parrakeet {Palaornis torquatus 9) 

 from India, presented by Mrs. O. Harvey ; a Redwing {Turdus 

 iliacus), British, presented by Mr. J. Newton Hayley ; a Com- 

 mon Viper ( Vipera bents), a Slowworm {Anguis fragilis), British, 

 presented by Dr. W. K. Sibley ; three Green Tree Frogs {Hyla 

 arborea) from France, presented by Mrs. Humphreys ; two 

 Hartebeests {Alcelaphus caama i 9 ) from South Africa, a 

 Bennett's Wallaby {Halmaturus bennetti i ) from Tasmania, a 

 Black Wallaby {Halmaturus walabatus 9 ), two Brush-tailed 

 Kangaroos {Petrogale penicillata i {, ) from New South Wales, 

 four Common Quails {Coturnix communis), European, de- 

 posited ; two Demoiselle Cranes {Grus Ttrgo) from North 

 Africa, purchased; a Japanese Deer {Cervus sika <J ), a Hog 

 Deer {Cervus porcinus 9), ten Cuming's Octodons {Octodon 

 cumingi), born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 Objects for the Spectroscope. 

 Sidereal Time at Greenwich at 10 p.m. on May 15 = 

 I3h. 34m, i8s. 



Remarks. 



(i) A question of great interest was raised last year by spec- 

 troscopic observations of the planet Uranus. As is well known,. 

 the spectra of Uranus and Neptune differ very widely from those 

 of the other planets. They show no solar lines in the visible 

 spectrum even when telescopes of very large apertures are em- 



