November 



NA TURE 



2\ 



chloride the solution was decanted and filtered. The greater 

 portion of the methyl alcohol was next removed by distillation 

 under the reduced pres-iure of l6o-20D mm. The remainder was 

 then treated with anhydrous ether, in order to completely pre- 

 cipitate the last traces of dissolved sodiam chloride. The liquid 

 eventually separated into two layers, an upper ethereal layer 

 containing about 5 per cent, of hydroxylamine, and a lower 

 layer containing over 50 per cent, of hydrjxylamine, the re- 

 mainder of the methyl alcohol, and a little dissolved salt. By 

 subjecting this lower layer to fractional distillation under 60 mm. 

 pressure, it was separated into three fractions, of which the first 

 contained 27 per cent, of hydroxylamine, the second 60 per 

 cent., and the third crystallized in the ice-cooled receiver in long 

 needles. This third fracti:)n consisted of free solid NHoOH. 

 Hydroxylamine as thus isolated in the free state is a very 

 hygroscopic substance, which rapidly liquefies when exposed to 

 air, owing to the absorption of water. The crystals melt at 33", 

 and the fused substance appears to possess the capability of 

 readily dissolving metallic salts. Sodium chloride is very largely 

 soluble in the liquid ; powdered nitre melts at once in contact 

 with it, and the two liquids then mix. Free hydroxylamine is 

 without odour. It is heavier than water. When rapidly heated 

 upon platinum foil it suddenly decomposes in a most violent 

 manner, with production of a large sheet of bright-yellow flame. 

 It is only very slightly soluble in liquid carbon compounds such 

 as chloroform, benzene, ether, acetic ether, and carbon bisul- 

 phide. The vapour attacks corks, so that the solid requires to 

 be preserved in glass-stoppered bottles. The free base appears 

 also to act upon cellulose, for, upon placing a few drops of the 

 melted substance upon filter paper, a considerable amount of heat 

 is evolved. The pure crystals are very stable, the base in the 

 free state appearing to possess much greater stability than when 

 dissolved in water. The instability of the solution appears, 

 however, to be influenced to a considerable extent by the alka- 

 linity of the glass of the containing vessel, for concentrated 

 solutions free from dissolved alkali are found to be perfectly 

 stable. Bromine and iodine react in a remarkable manner with 

 free hydroxylamine. Crystals of iodine dissolve instantly in con- 

 tact with it, with evolution of a gas and considerable rise of 

 temperature. Bromine reacts with violence, a gas again being 

 explosively evolved and hydrobromic acid formed. The nature 

 of the gas evolved is now undergoing investigation. A letter 

 from M. Lobry de Bruyn appears in the number of the 

 CItemiker Zeitung for October 31, warning those who may at- 

 tempt to prepare free hydroxylamine by the above method that 

 it is a dangerously explosive substance when warmed to a tem- 

 perature of 80"- 100'. Upon warming a flask containing the 

 free solid base upon a water-bath a most violent explosion 

 occurs. A spontaneous decomposition appears to set in about 

 80'', and even in open vessels the explosion is very violent. Care 

 must also be taken during the fractional distillation of the con- 

 centrated solution in methyl alcohol to cool the apparatus before 

 changing the receiver, as if air is admitted while the retort is 

 heated the experiment ends with an explosion. 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey (Macacus rhesus 9 ), two 

 Macaque Monkeys (Macacus cyitomolgus (} ? ), a Bonnet Mon- 

 key [Macacus sinicus ? ) from India, two Roseate Cockatoos 

 (Cacatua roseicapilla), a Greater Sulphur-crested Cockatoo 

 {Ccuatiia galerita), two Cockateels {Calopsitta noviT-hoUandue) 

 from Australia, presented by the Rev. Sidney Vatcher ; two 

 Rhesus Monkeys {Macacus rhesus 6 S ) from India, presented 

 by Mr. John H. Taylor ; a Macaque Monkey Macacus cynomol- 

 gus i ) from India, presented by Mr. K. A. Williams ; a Vak 

 [Pocphagus grunuiens i ) from Tibet, presented by Mr. M. E. 

 C. Ingram ; a Corn Crake(C/v v pratensis), British, presented by 

 Mr, E. Hart, F.Z.S. ; two Woodcocks [Scolopax rusticola), 

 NO. I I 49, VOL. 45] 



presented respectively by Mr. Hamon Le Strange^ 

 F.Z.S. , and Mr. William Bellamy ; two Water Vipers (Civ/cZ/nV 

 piscivorus), a Water Rattlesnake {Crotalus adatnauteus) from 

 Florida, presented by the Natural History Society of Toronto ;. 

 a Small-scaled Mastigure (Uromastix tnicrolepis) from Persia, 

 presented by Mrs. Howell ; an Alligator {Alligator mississippi^ 

 ensis) from the Mississippi, presented by Mr. W. Chattaway ;. 

 two Bearded Vultures {Gypaetus barbatus), European, deposited ; 

 a Molucca Deer {Ccrvus /noluccensis\ born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 

 The Telluric Spectrum.— Dr. Miiller has made some 

 observations of the telluric spectrum on the summit of the 

 Santis, and his results are given in a recent publication of Pots-- 

 dam Observatory (vol. viii.. No. 27). The observing stalioa 

 was situated at a height of 2500 metres above sea-level. It was. 

 found that when the sun had a mean aliitude, about 40 per 

 cent, of the lines due to the water vapour in the atmosphere 

 were quite invisible, and the remainder were very weak. Whilst 

 the zenith distance of the sun was less than 60°, the appearance 

 of the spectrum remained unchanged. At greater zenith dis- 

 tances the weak lines increased in intensity and the missing 

 ones gradually appeared. Measurements of the intensities of 

 single lines observed on different days and at different zenith 

 distances indicate a variation roughly proportional to the thick- 

 ness of atmosphere traversed. The aspect of the portion ol 

 spectrum observed was on the whole strikingly similar to that 

 seen when observations were made near sea-level on dry and 

 cold days. This is in agreement with the fact that the vapour 

 pressure on mountains in summer is approximately equal to that 

 on the plains in winter. Careful estimations of the intensities 

 of the atmospheric lines at C and D might therefore be utilized 

 to determine the decrease of the amount of vapour present in 

 the air at different elevations. With regard to other atmo- 

 spheric lines. Dr. Miiller observed change-i in the o-group. The 

 whole of the lines of this group, however, were easily seen at 

 the mountain station when the sun had a high altitude, and the 

 difference of intensity there and in the plains was considerably 

 less than in the groups C and D. Two maps are given illus- 

 trating the appearance of the lines in the neighbourhood ofC and 

 D for different zenith distances of the sun. 



Tempel-Swift's Periodic Comet.— The following ephe- 

 meris is given by M. Bossert in Astronomische Nachrichtett, 

 No. 3063 : — 



Ephemeris for Paris Midnight. " 



1891. Right Ascension. Declination. Brightness, 



h. m. s. ^ , 



Nov. 3 ... 21 31 22 ... -1- 7 496 ... loi 



M 5 • •• 21 37 6 ... 8 37-5 



„ 7 ... 21 43 17 ... 9 277 



„ 9 ... 21 49 59 ... 10 19-3 



,, II ... 21 57 13 ... II 15-1 ... 119 



,, 13 ... 22 4 59 ... 12 I2-I 



,, 15 ... 22 13 19 ... 13 11-2 



,, 17 ... 22 22 14 ... 14 I2'0 



,, 19 ... 22 31 45 ... 15 144 135 



,, 21 ... 22 41 54 ... 16 l8'0 



,, 23 ... 22 52 41 ... 17 22-2 



,, 25 ... 23 4 6 ... 18 26'6 



„ 27 ... 23 16 9 ... 19 3o'5 •■ I4"4 



„ 29 ... 23 28 48 ... 20 33-2 



Dec. I ... 23 42 I ... 21 33-9 



„ 3 ••• 23 55 46 ... 22 318 



,, 5 ... 09 57 ... 23 26-2 ... 14-0 



,, 7 ... o 24 30 ... 24 16-3 



„ 9 ... o 39 18 ... 25 1-4 



,, II ... o 54 15 ... 25 41-0 



,, 13 ... I 9 13 ... 26 149 ... 120 



The comet is moving north at the rate of 1° per day. It will 

 be in Pegasus all this month, and will pass about 4° north of 

 o Pegasus (Marcab) near the 23rd inst. The maximum bright- 

 ness is reached at the end of the month. 



Catalogue of Rutherfurd's Photographs.— A year 

 ago Dr. Lewis Kutherfurd presented to the Observatory of 

 Columbia College all his photographic negatives taken between 



