374 



NA TURE 



\ . Uigust 14, 1884 



Any sums which may accumulate from the interest of the fund, 

 above what is required for the purposes specified, are to be used 

 " in aid of investigation of meteoric bodies, to be made and 

 carried on by 'a citizen or citizens of the United States of 

 America." 



There being a notable difference between the determinations 

 i( specific weight of the normal hydrate of sulphuric acid, H.,SOj, 

 which have been made by Marignac in 1S53 and 1870, and later 

 on by MM. Schertel, Kohlrausch, Lunge, and Naeff, Prof. 

 Mendeleeff, aided by M. Pavloff, has recently determined it 

 again with all possible accuracy, and communicated the results 

 of his determinations to the Russian Chemical Society (Journal, 

 vol. xvi. fasc. 5). The hydrate was crystallised four times, 

 the operations being made in a perfectly dry atmosphere of 

 carbonic acid. Out of 6 kilogrammes, a remainder of only 300 

 grammes was received. The thus prepared hydrate melted at 

 lo°'i to io°'6, and an accurate titration of it gave the following 

 figures: Si 71, Si -52, and 81 '58, that is, on the average, 81 '6 

 per cent, of S0 3 , the theoretic percentage deduced from the 

 chemical formula being 81 '64. The specific weight of the 

 hydrate has been determined with great accuracy, and the average 

 result, with all necessary corrections, was 1 '83295 at ia 0- 02. 

 The reduction to 15 , as compared with water at 4 , being made 

 with Marignac's data for dilatation, the final result will be 1 '837 1 , 

 which figure differs only by croool from that of Marignac, and 

 widely differs from those of Kohlrausch, Lunge, and Naeff. 



When submitting the Baku naphtha to fractional distillation, 

 carried on at each 2°, Prof. Mendeleeff had shown that the 

 specific weight of the products of distillation, while rising on the 

 whole together with temperature, decreases however three times, 

 namely, between 55 and 62 , between So" and 90 , and between 

 105° and 110°. He shows now, in a recent communication to 

 the Russian Chemical Society {Journal, vol. xvi. fasc. 5), that 

 this is not a peculiar feature of the Baku naphtha, but that the 

 same decrease of specific weights is displayed also by American 

 naphtha, if this last be submitted to fractional distillation at 

 each 2°, and that the phenomenon is produced at nearly the 

 same temperatures. The products that boil below 60' were in- 

 sufficiently represented in Prof. Mendeleeff 's samples-; but from 

 60 3 (where the specific weight, reduced to 17 , like all following, 

 was 0-6642) until 124 (where it was 07322), there are two de- 

 : es of specific weight. Thus, at 80" it was 07347, but on 'y 

 07069 at 92°, that is, the same as at 75 . After that it increases 

 until 104 , where it reaches 07543 ; but it soon decreases fir a 

 second time, and at 115" to 117° it reaches 07270, that is, the 

 same figure as it had between 85° and 98°. Beyond 117° it con- 

 tinues to rise. Both kinds of naphtha — Caucasian and American 

 — however different their origin, thus display the same pheno- 

 mena at nearly the same temperatures ; the corresponding specific 

 weights, however, are not the same ; the portion at 8o° has, in 

 the Baku naphtha, a specific weight of 074S6, and only 07347 

 in the American ; and at loo the respective densities are 07607 

 and 073S0. The amounts of substance distilled at each tempe- 

 rature are also different. The researches will be continued in 

 Prof. Mendeleeff's laboratory. 



We have been requested to state that at the meeting of the 

 Essex Field Club, referred to in last week's Nature (p. 343), 

 the natural history and archaeological conductor who addressed 

 the Club on the " salting mounds " and other subjects was Mr. 

 Henry Laver, F.L.S., of Colchester. 



The additions to the Zoological Society's Gardens during the 

 past week include a Bonnet Monkey (Macacus sinicus i ) from 

 India, presented by Mr. T. S. T. Tregellas ; a Striped Hyama 

 (Hycena striata) from North Africa, presented by Sir John II. 

 Drummond Hay, K.C.B., C.M.Z.S. ; three Greater Sulphur- 



crested Cockatoos (Cacalua galerita), three Leadbeater's Cocka- 

 toos (Cacatua leadbealeri), a White-backed Piping Crow (Gym- 

 norhina leuconota) from Australia, a Red-sided Eclectus (Ecleclus 

 pectoralis) from New Guinea, a Blue and Yellow Macaw (Ara 

 ararauna) from South America, six Amherst Pheasants ( Thou- 

 malea amherstuc) from China, eight Himalayan Monauls (Lapko- 

 phorus impeyanus) from the Himalayas, two Javan Peafowls 

 (Pavo spicifir 6 i ) from Java, presented by Mr. Charles Clifton, 

 F.Z.S. ; a Rough-legged Buzzard (Archibuteo lagopus), British, 

 presented by Sir R. Payne Gallwey, Bart. ; a Cockateel 

 (Cahpsitta nova-hollandice), a Rose-Hill Parrakeet (Platycercus 

 eximius) from Australia, presented by Mr. J. W. Dixon; a 

 Green Turtle (Chelone viridis) from the West Indies, presented 

 by Mr. A. E. Painter, F.Z.S. ; a Loggerhead Turtle (Thalasso- 

 chelys caouana) from the Atlantic Ocean, presented by the 

 Surrey Commercial Docks Company ; a Leopard Tortoise (Tes- 

 ttulo pard ills) from South Africa, presented by Mr. William 

 Lane ; a Slow-worm (Anguis fragilis) from Norfolk, presented 

 by Mr. T. E. Gunn ; a Bonnet Monkey (Macacus sinicus) from 

 India, a Blue-fronted Amazon ( Chrysotis astiva) from Brazil, a 

 Grey Parrot (Psittaats erilhacus) from West Africa, an Alligator 

 Terrapin (Chelydra serpentina) from North America, deposited ; 

 two Jardine's Parrots (Pyocephalus gulielmi) from West Africa. 



two Conures (Conurus perlalus) from the Lower Amazons, 



an Electric Eel (Gymnotus electricus) from British Guiana. 

 purchased ; a Mule Deer (Cariacits macrolis), born in the 

 Gardens. 



OUR ASTRONOMICAL COLUMN 

 The next Minimum of Mira Ceti. — In the ephemeris of 

 variable stars for 1884 in the /"/.■■ ■'■'•', the next mini- 



mum of Mira is fixed to 1884 October 24, a date which does not 

 appear to result from Argelander's formula of sines, as it is given 

 in Schonfeld's Catalogue of 1875, viz. : — 



Epoch Min. = 1866 August S'o + 3313363. E 

 1 io^SsinP^.E + 2S2 45) 

 + 18-16 sin (** . E -f 31 15) 

 + 33'9°sin(^ . E + 70 s) 

 + 65-31 sin( j| . E + 179 4 s) 



For the present year E = 20, and hence substituting logarithms 

 the four perturbations become — 



+ [1-02036] sin (2I7°29) - - 6-35 

 + [1-25912] sin (113-07) = + 16-71 

 + [1-53020] sin (110-99) =+ 3''°5 

 + [1 -8149s] sin (207-07) = - 29-72 



The Julian date of the initial minimum is 2402S22, and we 



have — 



2402S22-0 



331-3363. E 6626-73 



Sum of perturbations ... ... ... + 12-29 



Julian date of next minimum ... ... 2409461-0 



Which it will be seen from the Nautical Almanac (p. 486) cor- 

 responds to 1884 October 11. In i^Sj by a very precise deter- 

 mination of the time of minimum, Schmidt found that it occurred 

 on December 16, which is 18 days earlier than the date given by 

 Argelander's formula, and the previous maximum had also been 

 earlier by about 19 days. If this correction still applies the next 

 minimum might be expected to fall about September 23, or a 

 month earlier than the Vicrteljahrsschnft has it. Still there is 

 the possibility that Prof. Schonfeld may have applied corrections 

 to the formula. 



The present year's minimum may be therefore advantageously 

 observed. In that phase Mira descends to about the bright- 

 ness of the well-known star following it, not far from the 

 parallel, or to about 8'5 m. 



