February 7, 1895] 



NA rUR£ 



347 



describes the base and its salts derived from toluene, analogous 

 to the compounds previously described by Prof. Meyer and 

 Merr Hartmann derived from benzene. In the second memoir, 

 Mr. Wilkinson describes a further series derived from para- 

 chlor-iodo-benzenc, C,.HjClI. The formation of both series 

 occurs precisely as in the case of the benzene derivatives. The 

 base derived from toluene was prepared from the para iodide of 

 toluene asstarlingpoint. Its composition is(C|;H4. Clla)^! . OH, 

 iodine apparently acting, as in the bases previously described, 

 in a trivaient capacity, and forming the central element around 

 which the two toluene radicles and the hydroxyl are grouped. 

 The base itself has only been obtained in atjueous solution, but 

 many of the salts crystallise well, and are consequently readily 

 isolated. The iodide, {C|,Hj . CII^).,! . I, is precipitated as a 

 white powder, extremely sensitive to light, and melting at 146^ 

 The corresponding chloride and bromide both crystallise from 

 water in needles which melt at almost the same temperature in 

 the neighbourhood of 178. The bichromate is a particularly 

 beautiful salt, crystallising from hot water iu large orange-red 

 plates. It is likewise explosive, detonating when heated. The 

 nitrate, (CgH, . CHj);! . NOj, is very soluble in water, and 

 melts at I39^ The per-iodide is a remarkable compound, 

 (C,;H4CH3)o( . r,, obtained by addition of two further .atoms of 

 iodine to the ordinary iodide above mentioned. It crystallises 

 in dark red needles, endowed with a very brilliant lustre, and 

 melting at 1 56 . In addition to these sails, double salts with the 

 chlorides of gold, platinum and mercury are described, all of 

 which crystallise well and exhibit definite melting points. The 

 base of the series described by Mr. Wilkinson possesses the 

 composition (C^HjCI).,! . OH, being deiived (rom para chlor- 

 iodo-benzene by reactions analogous to those by means of which 

 the base above described was obtained, and similar to those 

 previously described by Prof. Meyer. The iodide, chloride, 

 bromide, nitrate and chroniate, as well as double salts with the 

 chlorides of mercury and platinum, have been obtained in well- 

 defined crystals. Hence it would appear that the reactions 

 discovered by Prof. Meyer and Herr Hartmann, between 

 iodosoljenzene and silver oxide, and between sulphuric acid and 

 iodosobenzene, which resulted in the preparation of the first 

 iodonium bases, are of pretty general application in the benzene 

 series. These remarkable compounds containing iodine as the 

 grouping element must now, therefore, be regarded as 

 thoroughly well established, and the older idea as to the 

 nature of the iodine atom must give place to a fuller conception 

 of the capabilities of that element. 



Th e additions to the Zoological Society's Gardens during the 

 past week include a Chacma Baboon {Cyiiocephahis portarius) 

 from South .Vfrica, presented by Captain Webster ; a White- 

 throated Capuchin {Celni; hypoUiiciis) from Ccniral America, 

 presented by Mr. H. W. Manning ; a Senegal Parrot (Puo- 

 cephahis sencgaltis) from West Africa, presented by Miss 

 .-Mice Firman. 



OUR ASTRONOMICAL COLUMN. 



New Stars and Ni;bul.i;. — The first number of the Aslro- 

 physical yoitriial has come to hand. It is [jractically a con- 

 tinuation ol .■Islionomy aiiJ Ashv J'ity.<i,i in a slightly dilferent 

 form, and i> now pu'iished by ihe Cliicago University Pie-s. 

 Among the contributions to the journal is a paper, by Prof. W. 

 W. Campbell, on some interesting and significant changes 

 which have occurred recently in the S|iccirum of Nova Auriga:. 

 The intensities of the two lines at K 4J60 and \ 5750 appear 10 

 have decreased very materially. When I'rof. Caiii|itiell observed 

 the Nova spectrum in 1S92, these two lines were stronjcr in 

 the Nova than in the nebul;\; in the spectra of which they were 

 seen and piiotographed. Observing last November, however, 

 he found that this condition of things was reversed, the lines 



NO. I3IQ, VOL. 5 I 



appearing relatively fainter in the Nova than in the nebulce. As- 

 is now very well known, the specira of nebula; differ both as- 

 regards the number and inlensiiy of the lines. The recent 

 obseivations of the Nova seem to show that the spectrum is not 

 only nebular, but it is approaching the average type of nebular 

 specirum. Prof. Campbell thus sums up the bearing of 

 spectroscopic observations upon theories proposed to account 

 lor the genesis of new stars: — 



"The Harvard College Observatory has shown that both 

 Nova Aurigae and Nova Normse at discovery possessed sub- 

 stantially identical spectra of bright and dark lines, similarly 

 and equally displaced. Both diminished in brightness and botii 

 assumed tue nebular type of >pcctruiii. '1 he new star of 1876 

 in C)gnus probably had nearly an identical history : passing 

 from a bright star with a spectrum of bright and dark lii.es, to 

 a faint obj ct with a sptcirum consisting of one bright line 

 (undoul tcdly the nebular line A 5010, or the two nebu ar lines 

 A 5010 and A 4960 coml)ined). We may say that only five ' new 

 stars' have been discovered since the ap,ilication of the spectro- 

 scope to astionomital investigations, ant that tiiree of these 

 have had substantially identical speitroscopic histories. This 

 is a rtmaikable fact. We cannot say what the full significance 

 of this lai.t is. One result, however, is very clear : the special 

 theori.s proi ounded by various spettrostopists to account for 

 the phenomena observed in Nova AurigEe must unquestionably 

 give way to the mute gdiicial ihcoties." 



The Designation of Comets. — A uniform system of 

 conietary notation is certainly needed. The Observalnry 

 poinis out that though the small letters a, b, c, &c.,a'e now 

 generally used to denote the order of discovery, and Roman 

 numerals 1., II., HI., &c., to indicate the order of perihelion 

 passage, astronomers are not agreed whether to write Comet ■; 

 1894, Brooks's Comet, or Comet Hrooks. It is therefore sug- 

 gested, and the suggestion deserves to be acted upon, that 111 

 the future the order shall be letter, year, Komiu numir^l, dis- 

 coverer. The lull name of the comet would then run as fol- 

 lows : — Comet a 1892, I. (Swill) : and if any part of the name 

 be quoted, this order should be preserved. Those who have 

 had to search for observation of comets in astronomical publica- 

 tions, will welcome the system of unifoimity in indexing, pro- 

 po-ed by our contemporary. 



THE NEW CONSTITUENT OF THE 

 ATMOSPHERE.^ 



I. Densily of Nilrcgen from Various Sources. 

 In a former paper" it has been show that nitrogen extracted 

 from chemical compounds is about \ per cent, lighter than 

 ** atmospheric nitrogen, ' 



The mean numbeis for the weights of gas contained in the 

 globe used were as follows : — 



From nitric oxide 2'300I 



From nitrous oxide 2 2990 



From ammonium nitrite ... ... ... 2'2yii7 



while for "atmospheric nitrogen" there was found — 



By hot copper, 1S92 2'3loj 



By hot iron, 1S93 23100 



By ferrous hydrate, 1894 2 3102 



At the suggestioH of Prof. Thorpe experimenls were subse- 

 quently tried wiih nitrogen liberated from Krea l)y ihe action of 

 sodium hypobromite. Tfie hypobromite was prepared from 

 commerciaf materials in the proportions recommended lor the 

 analysis ol urea. The reaction was well under control, and 

 the gas could be liberated as slowly as desired. 



In the firat experiment thi gas was sulunitted to no other 

 treatment than slow passage through poiash and phosphoric 

 anhydride, but it soon became apparent that the nitrogen was 

 contaminated. The "inert ami inodorous" gas attacked 

 vigorously ihe mercury ol the Tupler pump, and was described 

 as smelling Tike a dead rat. As to the weight, it proved to be 

 in excess even of the weight of atmospheric nitrogen. 



The corrosion ol the mercury and the evil smelf were in great 



I Abstract of a paper by Lord Raytcigh, Sec. R.S., and Prof. William 

 Kaiiisay, F.K.b., read befure tile Koyai Suciely, .Tt a special mccung, on 

 Janu.iry 51. 



- l<.iylcigh, *' On an Anomaly encountered in Determinations of the 

 Densily ol Niiiogen Gas," Kov. ^oc. Pivc. vol. Iv. p. 340, 1S94. 



