542 



NA TURE 



[April 5, 1894 



nous flame forming aqueous vapour, carbon dioxide, and hydro- 

 fluoric acid. It liquefies at - 3° at the ordinary pressure to a 

 colourless mobile liquid which is without action upon glass. 

 The difference of boiling point between this liquid and propyl 

 chloride ( + 45°) is 48°, about the same as that between ethyl 

 fluoride and chloride, and almost twice as great as that between 

 the chlorides and bromides of the two radicles. The gas is de- 

 composed by melted sodium, with sudden and brilliant in- 

 candescence accompanied by deposition of carbon. It is soluble 

 in water to the extent of one and a half times the volume of the 

 latter. Isopropyl fluoride and allyl fluoride are prepared in a 

 similar manner from the corresponding iodides. They are both 

 gaseous substances capable of condensation to liquids by reduc- 

 tion of temperature or augmentation of pressure. A mixture of 

 allyl-fluoride with four times its volume of oxygen explodes with 

 great violence under the agency of an electric spark, or when 

 brought in contact with a flame. 



Fluoroform, CHF3, has been prepared in the pure state by 

 M. Me>lans only after repeated unsuccessful attempts. When 

 free fluorine from the platinum delivery tube of the electrolysis 

 apparatus is allowed to escape into chloroform an energetic re- 

 action occurs, chlorine is liberated, and in a few moments an 

 explosion is produced, with copious formation of carbon tetra- 

 fluoride and fluoroform. If the fluorine is caused to enter a 

 vessel containing air charged with vapour of chloroform an im- 

 mediate explosion is produced. When finely-powdered silver 

 fluoride and iodoform are mixed a vigorous reaction also occurs, 

 usually with incandescence, and the fluoroform produced is con- 

 taminated with other gaseous products. The reaction may be 

 modified, however, by adding chloroform and cooling with ice, 

 and the gas maybe purified from chloroform by passing through 

 alcoholic potash, which is without action upon fluoroform, from 

 carbonic oxide, which is usually present in small quantity, by 

 means of a solution of cuprous chloride in hydrochloric acid, fol- 

 lowed by desiccation over fused potash, and finally from last 

 traces of impurities by passage over silver fluoride heated to 150°. 

 The gas thus treated is pure fluoroform, a gas which liquefies at 

 0° under a pressure of twenty atmospheres. It is incombustible, 

 but imparts a bluish-green colour to a Bunsen flame when injected 

 into it. It is insoluble in water, and possesses an odour similar 

 to but feebler than that of fluoroform. The action of free 

 fluorine upon it is interesting. A flame is produced at the end 

 of the platinum tube delivering fluorine, and the one atom of 

 hydrogen contained in the fluoroform is extracted and converted 

 into hydiofluoric acid without any deposition of carbon, the 

 latter element being at the same time entirely converted to the 

 gaseous tetra- fluoride. 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey {Macactis rhesus) from 

 India, presented by Mr. W. Chrystal ; a Squirrel Monkey 

 {Chrysothrix sciurea) from Brazil, presented by Mrs. E. M. 



Parkinson ; two Bears {Urstis sp. inc.) from the Caucasus 



Mountains, presented by Mr. Arnold Pike ; a Striped Hyaena 

 {Hyccna striata) from North-west Africa, presented by Seiior 

 Don. D. M. Macleod ; a Kinkajou {Ccrcoleptes caudivolvuhis) 

 " from South America, presented by Mr. A. Murray ; a Hairy 

 Armadillo {Dasypus villosus) ; a Common Teguixin ( Tupinambis 

 teguixin) from h America, presented hy Captain W. Clift ; 

 an American Turkey {Meleagris gallo-pavo) from North 

 America, presented by Mr. Blayney Percival ; two Pink-footed 

 Geese {Anser brachyrhynchiis), British, presented by Colonel 

 W. H. Feilden ; a Greek Tortoise {Testiido grccca), European, 

 presented by Mr. George Hollis ; a Green Tree Frog {Hyla 

 arborea), European, presented by Mr. Thomas Plowman ; two 

 Pittas {Pitta sp. inc.) from Australia, purchased. 



NO. 1275, VOL. 49 1 



OUR ASTRONOMICAL COLUMN. 



The Reckoning of the Astronomical Day. — The 

 Canadian Institute, in cooperation with the Astronomical and 

 Physical Society of Toronto, have for some time had under 

 consideration the subject of astronomical time reckoning, and 

 last May the joint committee appointed sent out a circular- 

 letter for the purpose of obtaining the views of scientific men 

 interested in the matter. Answers were invited to the follow- 

 ing question : 



" Is it desirable, all interests considered, that on and after the 

 first day of January 1901. the Astronomical Day should every- 

 where begin at mean midnight ? " At the present time, as all 

 astronomers know, the astronomical day is reckoned from mean 

 noon to mean noon, and is 12 hours behind the civil day. 

 Hence, if the proposed change were adopted, the only differ- 

 ence between astronomical and civd times would be that the 

 former would have a twenty-four hour, and the latter a twelve- 

 hour notation. The astronomical day would therefore he 

 identical with the universal day, reckoning from o to 24 hours, 

 and commencing at midnight. From the fourth annual report 

 of the Toronto Physical and Astronomical Society, it appears 

 that 170 answers to the question had been receive". Of these, 

 107 were in the affirmative, and 63 in the negative. Twenty-one 

 astronomers in the British Islands thought the change desirable, 

 and four were against it. In the United State-, twenty-eight 

 astronomers favoured the departure from present cu>tom, and 

 ten opposed it. German astronomers are strongly against the 

 suggested change, as many as thirty-one replying in the negative, 

 while only seven sent affirmative answers. In fact, Germany 

 was the only country which furnished a majority of negative 

 answers. Most of the replies received were simply in the 

 affirmative or in the negative, but many were qualified in some 

 respect. All the categorical replies were in English, and of 

 the answers received from foreign countries, with notes written 

 in English, five were from Germany, four from Italy, four from 

 Austria, and one each from Russia, France, Norway, Holland, 

 and Colombia. As Miss A. A. Gray, who compiled the 

 answers, points out, this shows that the English language is 

 rapidly becoming an international medium for the communica- 

 tion oi scientific information. 



The Height of an Aurora. — Among the many interest- 

 ing comnmnications to the Astronomical and Physical Society 

 of Toronto during the year 1893, ^"^ contained in the volume 

 of the Transactions just received, is one by Mr. Arthur Harvey, 

 on the widely observed aurora of July 15. During the display, 

 an arch of auroral light rolled up out of the north, and passed 

 the zenith of Toronto, spanning the sky from east to we.^t. Its 

 width was fairly uniform, being from 5° to 7°. After lasting for 

 several minutes, its contiiiuiiy broke up in the east, it wavered at 

 the zenith, and soon vanished. Fortunately, Mr. G. E. Lumsden 

 saw the arch break up and vanish in the same manner. He 

 was at Bala, no miles north of Toronto, and saw the arch pro- 

 jected across the constellation Aquilla, at a point some five 

 degrees north of the celestial equator, or 40° south of the zenith. 

 At Toronto, Mr. Harvey saw the same arch at the same time 

 lying across Lyra, at a point about 10' south of the zenith. 

 From these observations the perpendicular height of the arch 

 v^as found to be 166 miles, and its breadth about 15 miles. If 

 the arch maintained an equal ■height above the earth, its ends 

 were I150 miles away, so that the magnificent sight was pre- 

 sented ot an auroral belt in the sky with 2300 miles between 

 its two extremities. 



An Annular Eclipse of the Sun. — There will be an 

 annular eclip>e of the sun to-morrow, which, however, will not 

 be visible in this country. It will be seen as a partial eclipse in 

 Norway and Sweden, Eastern Europe, and Asia ; and as a 

 central one along a line starting from a point in the Indian 

 Ocean, crossing India a little north of Madras, passing through 

 Calcutta, Upper Burmah, China, and Eastern Siberia. The 

 central eclipse begins at 2.24 a.m. Greenwich mean time, in 

 longitude 53° 48' east, latitude 6° 51' north, and ends at 5.23 

 a.m. in longitude 157" 38' west, latitude 62° 48' north. The 

 greatest duration of annularity will be about 32 seconds. An 

 eclipse of this kind excites but little scientific interest, the 

 chief observations of value being those of the times of the 

 four contacts. 



