April 7, 1892] 



NATURE 



547 



leaf is composed of a membranous portion, the placental 

 hemiphyll, and an ovular hemiphyll, which is entirely trans- 

 formed into the ovules with their funicles, together with the 

 style and stigma. The placental hemiphyll also takes part in 

 the formation of the pericarp and septa. The ovules originate 

 from the whole of the ovular hemiphyll, and not merely from 

 the carpellary margins or teeth. 



We notice the appearance of a very useful work, in Russian, 

 by Prof. Samokvasoff, on Russian prehistoric antiquities, 

 under the title of "Foundations of a Chronological Classifica- 

 tion of Antiquities, and Catalogue." As seen from the title, 

 the work consists of two parts : a catalogue of the very rich 

 collection of the Russian Professor, partly illustrated, and a 

 general description of the various epochs which may be 

 distinguished in the relics of the past on the territory of Russia. 

 He has no difficulty in showing that the Slavonians of the first 

 centuries of our era were by no means mere savages. The 

 burial places of that period, usually situated close to the earthen 

 forts, some of which must have required the work of a consider- 

 able population, contain hundreds and thousands of graves, so 

 that it is certain that the Slavonians of that period were living 

 in large societies, and had their fortified towns. The same 

 burial customs prevailed over large areas, but the treasures now 

 unearthed from various graves show that differences of wealth and 

 social position existed at that lime as well. Considerable amounts 

 of Greek, Roman, and Arabian gold and silver coins were found 

 in the graves, the metal alone of the coins found in some graves 

 attaining, at its present prices, the value of several hundred 

 pounds ; while numbers of objects of art, of Greek, Roman, 

 Byzantine, and Arabian origin, are proofs of the brisk foreign 

 trade which took place at that time. The graves of the pagan 

 Slavonians contain flax, woollen, silk, and gold-embroidered 

 tissues; ornaments in gold, silver, bronze, and bone; iron 

 weapons and parts of armament ; gold, silver, bronze, iron, and 

 clay vessels, and so on ; while the sickles and the grains of 

 wheat, oat, and barley which were found in the graves of South 

 Russia, together with small idols and other objects devoted to 

 pagan worship, are proofs of agriculture having been carried on 

 during the pagan epoch. 



Two new liquids containing fluorine have been synthesized 

 by M. Meslans. They are halogen derivatives of glycerin, and 

 were obtained by allowing allyl fluoride, a gaseous substance 

 recently described by M. Meslans, to react with chlorine and 

 bromine. Allyl fluoride, C3H5F, is readily prepared by the 

 gradual addition of allyl iodide to dry silver fluoride. It is a 

 colourless gas of peculiar odour, which burns with a luminous 

 flame upon ignition, with liberation of vapour of hydrofluoric 

 acid. When a jet from which chlorine is escaping is brought 

 into a vessel filled with allyl fluoride, combination at once 

 ensues, and drops of a colourless liquid commence to be deposited 

 upon the walls of the vessel. In order to obtain the liquid in 

 greater quantity a large flask is employed, through the caoutchouc 

 stopper of which pass two tubes, one delivering chlorine and 

 the other allyl fluoride. Considerable heat is developed during 

 the act of combination, hence the flask is immersed in a bath of 

 cold water. A slight excess of chlorine is maintained during 

 the reaction, and the liquid Avhich rapidly collects is- consequently 

 coloured green ; but when sufficient has been accumulated the 

 supply of chlorine is first arrested in order that the excess of 

 that gas, which produces the green coloration, shall be con- 

 verted to the colourless liquid by the still-issuing allyl fluoride 

 and the liquid thus decolorized. The colourless mobile liquid 

 so obtained is then submitted to distillation, when practically 

 the whole passes over into the receiver between 122° and 123°. 

 If the synthetical preparation is conducted volumetrically, it is 

 found that equal volumes of allyl fluoride and chlorine unite ; 



NO. 1171. VOL. 45] 



the resulting liquid [therefore presumably possesses the com- 

 position C3H5FCI.J, an assumption confirmed by a determination 

 of vapour density which yielded the number 4*50, the vapour 

 density calculated from this formula being 4-51. The compound 

 is indeed a derivative of glycerin, its constitution being probably 

 CHjCl — CHCI — CHoF, and may be termed dichloro-fluor- 

 hydrin. 



The second new compound is analogous to the one just 

 described, and resembles it very closely in properties. It is ob- 

 tained by the direct union of bromine with allyl fluoride. If a 

 few drops of bromine are allowed to fall into a vessel filled with 

 allyl fluoride, the latter is rapidlyj absorbed with considerable 

 rise of temperature, the red colour of the bromine simultaneously 

 disappearing. To prepare the liquid in quantity, allyl fluoride is 

 allowed to stream slowly into a quantity of bromine contained 

 in a cooled flask, the operation being continued until the red 

 colour of the liquid has entirely disappeared. The colourless 

 liquid thus obtained distils without decomposition at i62"'-i63°. 

 The data aff^orded by ^determinations of the bromine content 

 and the vapour density point to the formula CgHgFBra. Both 

 the liquids above described appear to be very stable compounds, 

 for even during their distillation the glass vessels containing 

 them exhibit no signs of etching. They are miscible with ether, 

 and readily soluble in absolute alcohol, but they are almost 

 perfectly insoluble in water. They possess pleasant odours, 

 somewhat reminding one of chloroform, and are sweet but 

 burning in taste. They are incombustible, but at a high tem- 

 perature the vapours burn with liberation of hydrofluoric and 

 hydrochloric or hydrobromic acids. 



The additions to the Zoological Society's Gardens during the 

 past week include a Guinea Baboon {Cyuocephalus sphinx ? ), 

 a Bateleur Eagle {Helolar.ius ecaudatus), a Puff Adder {Vipera 

 arielans) from isouth Africa, presented by Mr. Keith Anstruther ; 

 a Japanese Deer (Cervut sika ? ) from Japan, presented by Sir 

 Douglas Brook, Bart. ; a Wedge-tailed Eagle {Aquila audax) 

 from Australia, presented by Miss Carr ; a" fawny Owl 

 {Syrniurn aUico), European, presented by Mr. E. A. Rocheda ; 

 a Puff Adder [Vipera arielans) from South Africa, presented 

 by Mr. D. Wilson ; two Common Vipers ( Vipera berus), British, 

 presented by Mr. W. H. B. Pain ; a Shielded Eryx {Eryx 

 tkebaicus) from North Africa, deposited ; four Topela Finches 

 [Munia topela) from China, a Black-necked Swan {Cygnus 

 nigricollis) from Antarctic America, purchased. 



OUR ASTRONOMICAL COLUMN. 



The Relative Motion of 61 Cygni.— The large proper 

 motion of 61 Cygni, combined with its remarkable duplex 

 character, renders it an object of great interest. Doubts have 

 been expressed, however, as to whether the two components are 

 really connected by a bond of -mutual attraction, and it has been 

 assumed that they will gradually separate and traverse widely 

 different paths in space. Prof. A. Hall has brought together 

 all the observations which have been made of the position-angle 

 and distance of the star since 1825, and has investigated them 

 with a view of settling this question {Astronomical Journal, 

 No. 258). The result is in favour of the physical connection of 

 the two stars, but all that can be said of the period of revolution 

 is that it is very long. The mass of the brighter star appears to 

 be 3 '4 times that of the companion. 



The Temperature of the Sun.— Numerous attempts 

 have been made to determine the sun's temperature, and the 

 results obtained range from 1500° to 5,000,000 . The enormous 

 differences that exist between the different estimates result from 

 the fact that different laws have been assumed to represent the 

 rate of radiation. M. H. Le Chatelier communicated the 

 latest contribution to the subject at the meeting of the Paris 

 Academy of March 28. His experiments show that the intensity 



