2S6 



NATURE 



[January 12, 1893 



isolating pure salicylide. Salicylic acid is dissolved in an in- 

 different solvent, preferably toluene or xylene, before the addition 

 of the phosphorus oxychloride. The product of the reaction is 

 washed first with soda and afterwards with water. Owing to 

 the property, discovered by Prof. Anschiitz during the course of 

 the work, which salicylide possesses of combining with chloro- 

 form, it may be extracted from the white solid product, after 

 drying, by means of chloroform, the compound being deposited 

 from the chloroform solution in large colourless transparent 

 crystals belonging to the tetragonal system. The compound 

 possesses the composition CoH4.C0.0.2CHC]3. The chloro- 

 form readily escapes upon warming, in very much the same 

 manner as the water of crystallization contained in many 

 crystallized salts. The free salicylide remaining is a solid sub- 

 stance melting at 261°. As regards its molecular constitution 

 it is shown, by the amount of lowering of the melting-point of 

 phenol employed as a solvent, to contain four of the salicylic 

 radicles C6H4.CO.O, and is probably a closed ring compound. 

 In a precisely similar manner phosphorus oxychloride reacts 

 with the three cresotinic acids, the acids next higher than 

 salicylic, with formation among other substances of lactides, 

 which may be isolated in the same way in the form of their 

 chloroform compounds, CH3. C6H3.CO.O.2CHCI3. Ortho- 

 cresotinic acid lends itself best to this reaction. The pure lactides 

 are readily obtained from the chloroform compounds by warm- 

 ing to 100°, pure chloroform being gently evolved. 



The two substances above described, salicylide-chloroform 

 and the corresponding compound derived from ortho-cresotinic 

 acid, are admirably adapted for the preparation of pure chloro- 

 form, on account of their large content of the latter substance, 

 salicylide-choloroform containing 33*24 per cent, and the 

 cresotinic compound 30*8 per cent of its weight. Moreover, in 

 closed vessels they may be preserved anyjlength of time ; when 

 exposed to the open air salicylide-chloroform slowly loses its 

 chloroform, but the cresotinic compound is well-nigh stable, 

 even under these conditions. The same quantity of the free 

 lactide may be used over and over again without decomposition, 

 it being only necessary, in order to re-form the chloroform com- 

 pound, to allow it to remain in contact with the chloroform to 

 be purified for twenty-four hours at the ordinary temperature. 

 None of the usual impurities in chloroform crystallize along with 

 the compound, so that a perfect separation is effected. Again, 

 it is well known that pure chloroform decomposes more or less 

 on keeping ; this loss may be avoided by storing it in the form 

 of the lactide, and regenerating it when required by the appli- 

 cation of a gentle heat, with the certainty of obtaining it per- 

 fectly pure. 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey {Macacus rhesus ? ) from 

 India, presented by Mr. W. Stutely ; two Barbary Mice {Mus 

 barbarus) from North Africa, presented by Lord Lilford ; 

 four Bearded Titmice {Panurus biarmicus), European ; four 

 Ani {Crotophaga ant) from South America ; six Hog-nosed 

 Snakes {HeteroJon platyrhinos) ; a Striped Snake {Tropidonotus 



sirtalis) ; a Snake {Piinophis ), from North America, 



purchased. 



OUR ASTRONOMICAL COLUMN. 



The Motion of Nova Auriga. — Prof. W. W. Camp- 

 bell, of the Lick Observatory, has communicated further results 

 relating to Nova Aurigse to the December number of Astro- 

 nomy and Astrophysics. He is now perfectly convinced that 

 the variation in the velocity previously suspected is real, and 

 probably due to orbital motion. The values given below have 

 been calculated on the assumption that the brightest line in the 

 spectrum of the Nova, since the reappearance in August, is 



NO. I 2 II, VOL. 47] 



really the chief nebula line. The bright lines were displacecl 

 towards the violet, indicating approach, whereas in February 

 and March last they were displaced towards the red. 



Date. ^ Velocity of approach. 



1892. Miles per sec. 



Aug. 20 ... 5003-6 ... 128 



21 ... 37 ... 125 



22 ... 37 ... 125 



23 -. 3*1 ••• 147 

 30 - 2-4 ... 173. 



Sep. 3 ... 2-4 ... 173 



4 ... 1-9 •■• 192 



6 ... 2-1 ... 184 



7 ••• 19 ••• 192 

 15 ••• 2-2 ... i8a 

 22 ... 25 ... 169 



Oct. 12 ... 3-6 ... 128 



19 ■•• 3*8 ... 121 



Nov. 2 ... 4-4 ... 99 



3 -•• 47 ... 87 



In the same journal Mr. Sidgreaves points out that the new 

 lines cannot simply be revivals of those of February, and,, 

 further, that on account of the great difference of velocities and 

 the reversed direction, they cannot be supposed to belong to 

 the bright-line component of February. Neither is it likely 

 that the dark-line component has become a planetary nebula, 

 and the probability of three bodies rushing together being very 

 small, Father Sidgreaves believes the new results to strengthen 

 the view that the compound character of the spectrum was pro- 

 duced by local disturbances of a single star. 



Astronomical Discoveries in 1892,— In the Observatory 

 for January Mr. Denning gives an excellent summary of the 

 astronomical discoveries of 1892, a year which was very remark- 

 able for the special attention given to the science by the press 

 and the public. In chronological order the principal events 

 were as follows : — 



January 20. — Minor planet (324) discovered by photography 

 by Max Wolf at Heidelberg. (Altogether 27 were discovered 

 during the year by various observers.) 



January 23-30. — Discovery of Nova Aurigae by Dr. 

 Anderson. 



February \i. — The great sun-spot, extending over i5o,ooO' 

 miles of longitude, reached the sun's central meridian. This 

 was followed by remarkable magnetic disturbances and displays 

 of aurora. 



March 6.— Comet discovered by Lewis Swift. 



March 18.— Comet discovered by Denning at Bristol. On 

 this day also. Dr. Spitaler, of Vienna, re-detected Jhe periodical 

 comet of Pons (1819) and Winnecke (1858). 



August 6. — Opposition of Mars. Mr. Denning writes: 

 " Practically our knowledge stands where it stood before. The 

 results are not sufficiently discordant to settle disputed points." 



August 27. — A new comet discovered by Brooks, of Geneva, 

 N.Y. 



September 9. — Prof. Barnard's memorable discovery of the 

 fifth satellite of Jupiter. 



October 12. — Comet discovered by photography by Prof. 

 Barnard. 



November 6. — Bright comet discovered in Andromeda by 

 Mr. Edwin Holmes, London. 



November 20. — A faint comet discovered by Brooks. 



November 23. — ^Brilliant shower of shooting stars observed in 

 Canada and the United States. The shower was evidently that 

 of the Andromedes connected with Biela's comet. 



Comet Holmes. — Mr. Lewis Boss finds for this comet a 

 period of 6'9I4 years, and concludes that no very close ap- 

 proach to Jupiter can have taken place in recent years ; the 

 eccentricity, however, is so small that important perturbations 

 by Jupiter may have occurred. He further states that "the recent 

 remarkable decrease in brightness of the comet seems to do away 

 with the necessity of supposing that it has been recently made a 

 member of the solar system. This decrease also renders it 

 reasonably certain that the comet must have been subjected to 

 some extraordinary disturbance of its internal economy, by the 

 application of forces from without or within, with the result of 

 giving to it that which was really an unaccustomed and tem- 

 porary size and brightness " {Astronomical [ournal. No. 283). 

 According to Mr. Lockyer's views, such increase of brightness 

 would be produced by the comet colliding with-another meteor 



