6?2 



NA TURE 



[October 29, i< 



converts tlie same c|uantily of oxygen into the ' active ' slate, as 

 it itself takes up in the formation of the primary product of 

 oxidation." 



Thk theory of electrolytic dissociation, which is of such great 

 importance in modern chemical speculations, has been hitherto 

 almost exclusively confined, in its application, to aqueous 

 solutions. Notwithstanding the few investigations of the 

 electrical conductivity of solutions of salts in other solvents 

 which have already appeared, our knowledge of the ionisation 

 of such solutions is still very fragmentary. An extensive series 

 of measurements of the conductivity of solutions of salts in 

 methyl alcohol, published by Messrs. Zelinsky and Krapiwin 

 in the current number of the Zeilschrift filr physikalische 

 Cheniie, is therefore very welcome. They find that the methyl 

 alcohol solutions have, in many cases, conductivities of the same 

 order of magnitude as the aqueous solutions. For example, the 

 conductivities of methyl alcoholic and aqueous solutions of 

 potassium bromide of the same strength are in the ratio i : i'5 

 approximately, with tetramethyl-ammonium bromide the ratio 

 is I -I, and the dilute alcoholic solutions of trimethylsulphine 

 iodide possess almost the same conductivities as the aqueous 

 solutions. The influence of the change of solvent is more marked 

 with the acids ; oxalic and trichlor.icetic acids, for example, the 

 aqueous solutions of which are good conductors, possess very 

 small conductivities in methyl alcoholic solution. In all cases 

 the molecular conductivity increases with increasing dilution ; 

 he limit does not appear, however, to have been reached for 

 any of the substances examined. The niolecu ar conductivity 

 of some of the badly conducting substances increases with the 

 dilution in much the same way as is the case with aqueous solu- 

 tions of feebly dissociated substances, viz. approximately in 

 proportion to the square root of the dilution. For example, the 

 molecule conductivity of a .solution of tin diethyl iodide, 

 Sn(CoH5)2l2, increases I '36 times when the dilution is doubled, 

 i nstead of ^2 = i -41 times ; with trichloracetic acid the increase 

 s I -365 times. A curious fact, no explanation of which is as 

 yet forthcoming, is that the substitution of a sma quantity of 

 alcohol for water diminishes the conductivity of the aqueous 

 solutions considerably, and that the addition of a little water to 

 the alcohol used has the same effect on the alcoholic solutions. 

 Measurements of the conductivities of some salts dissolved in a 

 mixture of equal parts by weight of methyl alcohol and water, 

 show that they are almost exactly half those found in pure 

 water, or 25-30 per cent, smaller than those found in pure 

 methyl alcohol. 



The additions to the Zoological Society's Gardens during the 

 past week include three Purple-faced Monkeys {Sciiinopithecu, 

 IciicopryiHiitis] from Ceylon, a Rhesus Monkey (.l/i!(-a</(.v?-/i«;«), 



a Bamboo \<.3X{Rhizomys, sp. inc. ), a Mouse [Mits, sp. 



inc), three Doves (Turliir, sp. inc.), eleven Burmese Tor- 

 toises {Testiido clongata), seven Black-backed Tortoises [Testudo 

 platyiwta), three Ceylonese Terrajjins [Nicoria trijtiga, var- 

 edem'aiia), four Shielded River Turtles (Emys sciitnta), five 

 Cocteau's Geckos {Hemidadyhis loctiei), twelve Verticillated 

 GecV.0!, (Get koverluiHatiis), six VeUowish Monitors ( Firraw/M 

 flavesceiis), six Doria's Lizards {Mabiiia dori,c), .six Emma's 

 Lizards [Calotes emma), three Bell's Lizards {Liolepis bclliana), 

 five Robed Snakes (Tropidonotus stolatiis), two Fishing Snakes 

 (Tropidonottis ptscator), a Rayed Snake [Coluber radialiis), a 

 Condenar Sand-Snake {Psaiinnophis condanarus), two Well- 

 spotted Snakes {Dipsadoiiiorpliiis ntiiltimaculatiis), two Oliv- 

 aceus Water-Snakes (Hypsirhina en/iydris), an Aulic Snake 

 (/.ycodon auliciis), two Ornamental Tree Snakes (Chrysopelea 

 oiiiata), four (Srass-Green Tree Snakes {Dryophis prosina). two 

 Long-snouted Snakes (Passcrita myclerizaits), a Hamadryad 

 (Ophiophagiis claps), a Banded Bungarus (Btingariis fasciattts), 

 NO. 1409, VOL. 54] 



an Indian Cobra (Naia Iripiidiaiis), three Russell's \'ii)er, 

 ( Vipera russellt), eleven Green Pit-Vipers (Laclicsis gramiiieti.] 

 from Burmah, presented by Mr. W. C. Bligh ; a Black Lemur 

 (Lemur macao) from .Madagascar, presented by Captain 11. 

 Talboys ; a Black Wallaby (Halmaturus nalabatus) from Neiv 

 South Wales, presented by Mr. Malcolm Watson ; a Moorish 

 Tortoise ( Testudo maurilauica) from North Africa, presented liy 

 Mr. R. .M. C. Souper ; a Yellow-cheeked Lemur (Lemur 

 xantliomystax) from Madagascar, presented by .Mr. II. O. 

 Townshend ; a Smith's Dwarf Lemur (Microcebus smithi) from 

 Madagascar, presented by Dr. Hubert \i. ]. Bliss ; two Panolia 

 Deer (Cervus etdi) from Burmah, deposited ; two Virginian 

 Eagle Owls (Rnho virgiiuauus) from North America, pur- 

 chased ; a Great Eagle Owl (jS///itf ma.xintus) ICuropean, received 

 in exchange. 



OU/i ASTRONOMICAL COLUMN. 



Comet 1870 II. — This comet was discovered on August 28, by 

 Coggia in Marseilles, and was last observed by Pechiile in 

 Hamburg. During the period of its visibility it described a 

 heliocentric arc of about 59". On September 26 it approached 

 its least distance from the earth, this being measured as 0-885 

 radii of the earth's orbit. In appearance the comet resembled 

 a nebular mass with a perceptible nucleus ; it varied, however, 

 consideralily, sometimes appearing without a nucleus, while at 

 other times several nuclei were observed. Up to the present 

 time the ephemeris obtained from the elements, computed by 

 Gerst, represented very well the observed positions. 



These elements were as follows : — 



T = 1870 September 2-23393 Berlin Mean Time. 



7r = 7 53 19-0 1 

 fl = 12 56 22-4 [• 1870-0 

 i = 99 20 45 9 I 

 log ,/ = o 259288 



Dr. Anton Schobloch has, however, undertaken the investiga- 

 tion of determining more thoroughly the elements of this comet. 

 In this calculation he has included 311 observations, made at 

 various observatories. The main figures in the computation 

 will be found in Astronomischc XaJiridilen (No. 3383), 

 together with the list of the observations and comparison stars 

 used. The result shows, however, that there is no reason to 

 depart from the assumption of a parabolic orbit. The final 

 elements, as given below, differ only slightly from those obtained 

 by Gerst. They are, as the following figures show : 



Mean Equinox, 1870-0. Osculation, ^September IVS, Berlin 

 Mean Time. 



T = 1870 September 2-2318232 Berlin Mean Time. 



"^ = 7 S3 I5"i4| 

 a = 12 56 18-78 • Ecliptic 

 / = 99 21 3-9o| 

 log ,/ = 0-2592768. 



Comet (Ii.^cobini. — This comet isnotavery bright object in 

 the heavens, but as Prof. Kreutz appeals for more observations 

 to enable an accurate determination of its period possible, we 

 give the following ephemeris. The elements on which this is 

 based are those obtained by Messrs. Perrotin and Giacobini 

 from observations made on September 4, 12, anil 27. .\ glance 

 at the ephemeris, given in Aslr. Naeh. (No. 3384), shows that 

 the southern declination of the comet commences, about 

 November 3, to decrease. 



Epiieuieris for \2/i. Berlin Mean Time. 



19 59 27 -13 45-7 



