yan.2>, 1874J 



NA TURE 



193 



Messrs. Lovell, Reeve, and Co., have in the press a 

 volume on St. Helena, comprising a physical, historical, and 

 topographical description of the island, with its geology, fauna, 

 flora, and meteorology. The author is Mr. J. C. Melliss, C.E., 

 F.GS., F.L.S., late Commissioner of Crown Lands, Surveyor 

 and Engineer of the Colony. 



The Scotsman reports that a piece of gold-bearing quartz has 

 been found in the island of Bute. 



Bee-keeping has become a vocation or avocation of so much 

 importance in America that there actually exists a "North 

 American Bee-keepers' Society," which, like more important 

 associations, meets yearly in one of the towns of the States. 

 This year the scciety met at Louisville and continued its sittings 

 for several days. Among the papers read was one by Genera^ 

 D. L. Adair against the practice, common among apiarians, or 

 clipping the wings of the queen, the paper .showing a very con- 

 siderable acquaintance with the structure of the bee. 



The Times takes the following from an American paper, and 

 asks " Why not in London ? " : — " In Pittsburg, Pennsylvania, 

 an electric dock has been established to move the hands of 

 seventy different clocks, scattered all over the city. The motive 

 clock is powerful, and has a pendulum composed of hollow coils 

 of copper wire. These swing to and fro over the poles ot horse- 

 shoe magnets, and every time they pass from one pole to the 

 opposite a current of electricity is called up inductively in the 

 coils, flows up the wire, and then to the seventy dials, giving a 

 current of an opposite nature at each swing. Behind each dial 

 is an astatic permanent magnet, suspended on a pivot, and 

 surrounded by a coil of wire, and it rotates under the electric in- 

 fluence from the wires. A small weight may be used to each 

 dial if the hands are heavy, and the pivoted magnet may merely 

 regulate the time. Of course every clock will be exactly alike, 

 and will run with very little attention. To prevent the pendu- 

 lum of the motive clock from moving too fast by the increase 

 in the length of vibration of the pendulum, a magnetic bridling 

 apparatus is attached." 



A letter appears in the Times of the 30th instant, from a 

 correspondent with the "Livingstone East Coast Expedition," 

 dated Mdaburu, Ugogo, Central Africa, July 15, and is princi- 

 pally occupied with a description of the many annoyances to 

 which the expedition was subjected. 



The finest kitchen garden in France is that of Versailles, 

 which belongs to the State, and brings in a yearly revenue, 

 taking good and bad years together, of about 20,ooof. Tlie 

 Assembly has determined to apply this valuable property to the 

 formation of a model market garden and school of horticulture. 

 The details of the institution are not yet arranged, but it is 

 presumed that it will be self-supporting, and that it will render 

 valuable assistance in the development of horticultural science in 

 France. 



The additions to the Zoological Society's Gardens during the 

 past week include two Violaceous Plantain-cutters (Musop/iaga 

 violacea) from W. Africa, purchased ; two Senegal Touracous 

 (Coryt/iaix persa) from W. Africa, presented by Mr. Hawkins ; 

 two Chinese Storks (Ciconia Bavcei) from China, presented by 

 Mr. R. B. Boyce of Shanghai ; a Grivet Monkey {Cercopithicus 

 lalandii) from W. Africa, presented by Mrs. Couteam ; a Coati 

 (IS^asua ttasica) from S. America; three Derbian Streamers 

 (C/iauiia dcrbiana) from Columbia ; a Chinese Water Deer 

 (HydroMes inermis) ; a Common Otter (Ltilra vulgaris), 

 British, deposited ; two Black-tailed Hawfinches (Coccot/iausles 

 mtlatiHi-us) from China, purchased. 



ON THE SPECTRA OF COMETS* 



HTHE spectrum-analytic method of examining the light from 

 •*- comets has only been applied hitherto to comets of weak 

 light ; yet the observations are fitted to extend considerably our 

 knowledge of these objects. The spectra of all the comets that 

 have been examined have consisted of a few bright lires or bands 

 of light, and a very faint continuous spectrum. The chief part 

 of the comet's Hght appears, accordingly, to be proper to it, and 

 is probably from glowing gas, while the remaining portion is re- 

 flected sunlight. 



Among the brightest comets which have appeared since the 

 introduction of spectrum analysis are those of Brotsen (I. 1S68) 

 and Winnecke (II. iSoS). The spectrum of the formt r consisted 

 of three bright bands, whose position Huggins sought to deter- 

 mine with great accuracy ; but he found no coincidence with the 

 spectral lines of any terrestrial substance. The spectrum of 

 Winnecke's comet, also examined by Huggins, was somewhat 

 different, but similarly consisted of three bright bands (in addi- 

 tion to the continuous spectrum always present), which were 

 sharply defined on the side nearest to the red end of the spec- 

 trum, but diffuse on the other. A comparison of the comet's 

 spectrum with that of olefiant gas showed striking similarity 

 between them ; and Huggins was able to establish, with some 

 certainty, a coincidence of the three bright bands. The expressed 

 opinion that the material of this comet might be hydrocarbon 

 found general acceptance ; and the inference has been extended to 

 other comets, so that it has been taken as demonstrated, that the 

 comets are formed of hydrocarbons. (Dr. Zenker in Astr. 

 iVac/ii: Nos. 1890 to 1893.) 



I will now give a summary of all the observations knomi to me 

 of cometary spectra, from which it will be seen how far the con- 

 clusion in question is warranted. 



1. The first comet examined by spectrum-analysis is the Comet 

 I. 1864. Donati found its spectrum to consist of three bright 

 bands, which (if one may judge from the figure in Ash: Nachr. 

 No. 1488) do not coincide with those of the hydrocarbon 

 spectrum. 



2. Huggins and Secchi observed Tempel's Comet I. 1866, 

 and got from it a weak continuous spectrum, in which Secchi 

 saw three bright lines, Huggins only one The line seen by 

 both was the brightest, and situated m the middle between i^and 

 F of the solar spectrum ; accordingly no coincidence with the 

 hydrocarbon spectrum. 



3. In the spectrum of Comet II. 1867, the continuous spec- 

 trum was relatively so strong that Huggins found it difficult to 

 detect bright lines. "Once or twice," he says, " I suspected 

 the presence of two or three bright lines, but of this observation 

 I was not certain. The prismatic observation of this faint object, 

 though imperfect, appears to show that this small comet is pro- 

 bably similar in physical structure to Comet I., 1866." In this 

 case, again, probably no hydrocarbon. 



4. Brorsen's Comet I. 186S, was observed by Huggins and 

 Secchi. Both observed three zones of light ; the middle one 

 being brightest, and lying in the green ; while its brightest part 

 was somewhat less refrangible than the brightest line of the air 

 spectrum (wave-length = 50O'3 mill, millim.). From this ob- 

 servation, and the determination of the position of the other two 

 faint bands, it appears that the comet spectrum was neither 

 similar to that of nitrogen, nor to the hydrocarbon spectrnm. 



5. Winnecke's Comet II. 1S6S, was also observed by Huggins 

 and Secchi. The measurements and direct comparisons of 

 Huggins gave an agreement of the cometary spectrum with that 

 of carbon in olefiant gas. From Secchi's measurements it ap- 

 pears, that the sharply defined side of the middle band (towards 

 the red end), nearly coincided with the line-group b of the solar 

 spectrum ; at which part also the beginning of the middle band 

 in the spectrum of hydrocarbons is situated. 



6. Comet I. 1870 was observed by Wolf and Rayet ; the 

 spectrum consisted of three bright bands, whose position, how- 

 ever, was not accurately determined. 



7. Comet I. 1S71 was observed by Huggins and myself. 

 Huggins found three bands, I only ttvo. The measurements of the 

 bands observed in common agree well ; the spectrum appears to 

 be identical with that of Brorsen's comet. 



8. Comet III. 1871 (Encke) was observed by Huggins three 

 days, by Young four, and by myself six ; it showed, as usual, a 

 spectrum of three bands. Huggins thought this agreed with 



* Abstract of paper in Poggendorfif's Annalei), by H. Vogel. 



