i.«i8 



NA TURE 



[June 15, 1893 



aluminium chloride and the ketone, (R.CO.Rjj. AIjCIj, with 

 elimination of hydrochloric acid. Under the conditions of the 

 experiment this latter compound is dissociated into free alumi- 

 nium chloride and ;the free ketone. That this explanation is 

 very near the truth is demonstrated by the fact that by working 

 in carbon bisulphide solution, M. Perrier has actually converted 

 his new compound with benzoyl chloride, (CjHjCOCOj, AljClj, 

 directly into the ketone compound, (C5H5.CO.C6H5)2.Al.^CIe, 

 by reacting upon it with benzene. The crystals of the ketone 

 compound obtained were identical with these prepared from 

 benzophenone itself. 



We regret that in announcing the birthday honours last week 

 the name of Mr. Daniel Morris was printed "Mr. David 

 Morris." 



Notes from the Marine Biological Station, Plymouth. — Last 

 week's captures include the Actinian Chitoiiactis coronata, the 

 Polychaeta Clycera capilata and Proceraa picta, the Opistho- 

 branchs Cahdiella plebeia and Triopa claviger, the Schizopod 

 Leptomysis mediterranea, the Ascidian Pyciioclavella aurilucens 

 and a number of Amphioxus ianccolatiis. The character of the 

 floating fauna has exhibited little change since the preceding 

 week, Ctenophora and Leptomedusce having been especially 

 abundant. The following animals are now breeding : Various 

 Serpulidas, the Schizopoda Schisiomysis arcnosa and Leptomysis 

 mediterranea, the Decapod Crangon scnlptus, and the Ascidian 

 Botryllus violaccus. The majority of Amphioxus also are full- 

 grown and mature. 



The additions to the Zoological Society's Gardens during the 

 past week include a Stair's Monkey (Cercopithecus slairsi, i) 

 from East Africa, presented by Mr. F. Hintze ; a Himalayan 

 Bear {Ursus tibetaniis, i) from Northern India, presented by 

 Capt. Michael Hughes, 2nd Life Guards ; a Maugcj Dasyure 

 (Dasyurus matigm) from Australia, presented by Mr. Robert 

 Hoade ; four South Island Robins {Miro albifrons) from New 

 Zealand, presented by Capt. Edgar J. Evans ; two Carri n 

 Crows {Corviis eorone), British, presented by the Hon. \Vm. 

 Edwardes ; a Rose-crested Cockatoo {Cacatna moluccensis) from 

 Moluccas, presented by Mr. J. B. Sutherland ; a Herring Gull 

 (Larus argentatus) British, presented by Miss M. A. Croxford ; 

 a Long-eared Owl (Asio otus), a Tawny Owl {Sjrniiim aluco), 

 British, presented by Mr. Alan F. Grossman ; two Horned 

 Lizards {Phrynosoma cornulmn) from Texas, presented by Mr. 

 A. E, Jamrach ; a Red-handed Tamarin [Midas riifiiitaitus) 

 from Surinam, a Yellow-footed Rock Kangaroo [Pflrogale 

 xanthopus, <5 ) from South Australia, fourteen Horned Lizards 

 [Phrynosoma eornutum) from Texa?, four Tuberculated Iguanas 

 {/guana tuherculata) from the West Indies, deposited ; a 

 Malbrouck Monkey [C^rcopiihccus cynosurus) from West Africa, 

 four Bronze-winged Pigeons [Phaps chakoplera), two Australian 

 Sheldrakes (Tadorna tadornoidcs, i ?) from Australia, four 

 Green Waxbills (Estrelda formosa) from India, purchased ; a 

 Vervet Monkey [Cercopithecus lalandii), a Japanese Deer 

 [Ctrvus sika, 9 ) born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Finlay's Comet (1886 VII.). — The ephemeris of Finlay's 

 comet for this week is as follows : — 



Determinations of Gravity.— The Appendix (No. 15) of 

 the report of the "United States Coast and Geodetic Survey 

 for 1891 " contains a set of determinations of gravity made with 

 half-second pendulums on the Pacific coast, in Alaska, and at 

 Washington, D.C., and Hoboken, N.J., under the superin- 

 tendence of Mr. T. C. Mendenhall. On account of the difficulty 

 and cost of a previous undertaking, the apparatus in the 

 present determinations has been greatly reduced both in magni- 

 tude and complexity by using a pendulum vibrating to half a 

 second and a chronometer in place of a clock. The pendulum 

 apparatus consisted of a set of three-quarlermetre pendulums, a 

 dummy or temperature pendulum, an air-tight receiver in which 

 the pendulums were swung, a flash apparatus, wherein an 

 electromagnet in the circuit of a chronometer moves a shutter 

 and throws out a flash of light each second, a telescope for ob- 

 serving, mounted above the flash- light apparatus and various 

 accessories. The pendulums themselves constituted a set of 

 three, so that discrepancies in any one of them, if they appeared, 

 could easily be detected. Each was composed of an alloy of 

 aluminium 10 per cent, and copper 90 per cent., a composition 

 highly resistible to corrosion. The base station adopted was 

 at the Smithsonian Institution in Washington, and the value 

 assumed there for^ was 98010 dynes. 



The following are the values of^as obtained at five place:;, a 

 table given here including several other deteiniiuations : — 



Long. Efev. g 



Station. Lat. N. W. of above .,.fi„„ reduced to- 



o , o , Feet. Dynes. Dyn<s. 



Washington, D.C. 38 S3 77 °2 34 [9S0 loooj 980-1020 



San Francisco, Cal. 3747 12226 375 9799507 9799727 



Seattle, Wash. 4736 121 20 243 9S07116 9807258 

 Mount Hamilton, ) 



Cal. [ 37 20 121 39 4205 979'6456 979'892» 

 Lick Observatory } 



Hoboken, N.J. 4044 7402 35 980-2555 980-2576 



Solar Observations at the Royal College, Rome. — 

 In the Memorie della Societh degli Spettroscopisti Italiani Prof. 

 Tachini communicates the observations of the sun made at the 

 Royal College Observatory during the first trimestre of this 

 year. The records of the protuberances during this period show 

 that the monthly numbers were 138, 198, 264, a rapid increase, 

 as will be noticed, the maxima heights being 1026", 1149", 

 and 1650" respectively for the same months. The mean ahi- 

 tudes increased also rather irregularly, 706", 824", and 1103" 

 being the numbers given. With regard to the spots, Ma:"cb 

 contained the most numerous (358), being 94 more than January 

 and 73 more than Fel ruary. The number of groups for ihe 

 first two months were, curiously enough, nearly equal (the 

 numbers being loi and 102), but the extensions were very 

 different, 1968 and 2215 representing Ihe numbers for the spots, 

 and 8';0 and 1170 for the faculie. The same number of these 

 memoirs gives a summation of the solar observations made at 

 the Royal Observatory at Palermo during the year 1892 by .\f. 

 T. Lona and A. Maseari, and M. u^betli's observations of the 

 conjunction of Mars with v Tauri, and of Saturn with y 

 Virginis. 



L'Astronomie for Ji;ne. — The opening article in this 

 month's number contains a description of a very remarka ile 

 observation on Jupiter made by M. Lumsden on September 20, 

 1891. It seems that he has seen the shadow of the first 

 satellite of Jupiter on the planet's surface, accompanied and 

 followed by a second shadow, not so dark and sharp as the 

 original satellite, but nevertheless very distinct and incon- 

 testable. This second shadow is said to have moved uniformly 

 with the real one, following it at an equal distance. The ob- 

 server seems to be very certain that it was not a spot, so the 

 question is — How can this secondary shadow be explained i* 

 It was thought at first that as the other satellites were all on the 

 same side of the primary it might have been one of their 

 shadows, but the facts show that that was not the case. M. 

 Lumsden suggested that perhaps it was the shadow of Satellite 

 I cast by the light emitted by Satellite 4, assuming the fourth 

 satellite to be self-luminous, but M. Flammarion's explanation, 

 is perhaps more simple, it being that since the atmosphere of 

 Jupiter is very deep, the clouds would be at various depths, and 

 at great distances from one another, so that sometimes the 

 sh.idow of a satellite would fall either on the upper or on the 

 lower clouds, or even on the disc itself. It is true that the dis- 

 tance between these shadows would be very small as seen froni 



