April 2, 1874] 



NA TURE 



433 



meteorites, composed principally of iron and nickel. While on 

 the other hand, in the case of stars of the third class, in which it 

 seems excessively probable that we have both metalloids 

 and compounds, and very little pure metal, that is to say, metal 

 not in combination, in the reversing layer, we have also the 

 large class of silicate meteorites, the origin of which is pos- 

 sibly due to such stars in exactly the same way as the origin of 

 the iron meteorites would be due to stars of the second class. 



If this be so, then it would seem that a comet is simply a 

 meteorite which contains something which is volatile at a very 

 low temperature. Amongst the vapours known to chemists, 

 which are volatile at the lowest temperature, are the hydro- 

 carbons. I have already pointed out to you that as far as obser- 

 vations have gone on comets we have been able to delect nothing 

 but the possibility of a spectrum of carbon, _or of a compound of 

 carbon. 



Here again dhnly and darkly the prism is pointing us to a 

 possible connection between all the stars in heaven and all the 

 comets and all the meteors which flit through the celestial spaces 

 and fall upon our own earth. 



I have already referred to the verdict of the prism in connection 

 with the nebukv, and there can be very little doubt, I think, that 

 before the world is very much older the prism will also be per- 

 fectly competent to connect nebulce with stars as it may possibly 

 have already connected comets and meteors with them ; but this 

 point certainly is at present one of great difficulty, and it is a dif- 

 ficulty which no student of science will care to get out of, since 

 in matters of this kind a difficulty is a matter of the highest im- 

 portance, showing you as it does that part of the field of nature 

 which recjuires most siudy. 



I quite feel that this enormous subject, which modem science 

 is opening up, is one the importance of which is so great and the 

 interest in which is so general that I am sorry that the task of 

 talking about it has not fallen upon the shoulders of one who is 

 more competent to do it than I am. I hope, however, that 

 feeble as my advocacy may have been, you are prepared to agree 

 that the time will come when Celestial Chemistry, as investigated 

 by means of the prism, will be acknowledged to be one of the 

 most important branches of modem science. 



J. Norman Lockyer 



SCIENTIFIC SERIALS 



Journal of the Franklin Institute, February. — In this num- 

 ber Mr. Prindle has a paper (with numerous illustrations) On 

 Recent Improvements in Construction of the Gunpowder Pile- 

 driver. — A long and instructive paper by Mr. Loiseau, On Arti- 

 ficial Fuel, gives a resume of what has hitherto been done in this 

 direction ; the author describing his own method, in which a 

 mixture of 5 per cent, clay and 95 per cent, coal-dust, moistened 

 with milk of lime, is moulded into oval lumps, which are then 

 bathed in a waterproofing liquid (rosin dissolved in crade ben- 

 zine) and dried. With 14 men only, a production of 150 tons 

 per day can, it is said, be easily attained. — Prof Houston an- 

 nounces the discovery of a new allotropic modification of phos- 

 phorus, obtained by boiling good phosphorus repeatedly in 

 potassium hydrate (under certain conditions). This new modi- 

 fication retains for an indefinite time, apparently, the liquid state, 

 even when exposed to temperatures considerably below the 

 melting-point of ordinary phosphorus, from which it also differs 

 in its non-oxidation on exposure to air, and, consequently, its not 

 shining in the dark. — Mr. Chesebrough describes the construc- 

 tion of the Detroit River Tunnel ; and Prof. Thurston has a 

 note relative to the estimation of the chemical value of coals con- 

 taining large quantities of ash. — Among the " Items and Novel- 

 ties," it is stated that Prof. Thurston has gone very carefully into 

 the subject of a scheme published by Mr. Chesebrough, for 

 keeping canals open in winter by warming the water. The pro- 

 fessor's calculations are given, and he finally arrives at an esti- 

 mate of 5,412,500 dols. as the first cost of apparatus lor a canal 

 350 miles long, 70 feet deep, in the latitude of Central New 

 York ; and 1,670,200 dols. for the maintenance per annum. 

 He thinks the scheme deserving of investigation. 



As/rotiomise/ie A'i!c/:rie/it(n, Nos. 1,976 and 1, 977. — Thesenum- 

 bers contain a paper by M. Lohse on the estimation of the 

 depth of sun-spots, and at the same time to ascertain the influ- 

 ence of solar refraction. The principle of his method is as fol- 

 lows : — When a spot having its umbra concentric with penum- 

 bra, when seen from the vertical, is seen near the sun's limb, the 



umbra becomes excentric, and the depth of the umbra p' will 



and a the heliocentric position-angle of the spot from the axis, 

 and assuming the spot steady, p' should remain constant as a and 

 with it e change. This, however, is found not to be the case, 

 for/' gradually increases as the spot gets from the limb, showing 

 it was raised by refraction at the limb, and therefore this change 

 in the value of/' gives a measure of the sun's refraction. The 

 same author also contributes a paper on the effect of the atmo- 

 sphere of Venus in the transit over the sun, and he recommends 

 the examination of its atmosphere with the spectroscope for ab- 

 sorption-bands. — J. Hortazzi gives the observations of transits 

 for longitude of Nikolagew.— J. Palisa gives a large numb r of 

 ring-micrometer observations on the minor planets and a few 

 comets. — Dr. Holetschek gives the position of some seventy com- 

 parison-stars for planets and comets. — E. Stephan gives a list of 

 ten new nebulee discovered and observed at Marseilles ; all seem 

 excessively small. The elements of the new comet are given by 

 Wilhelm as follows : — 



T = March 9 "8 125 Berlin time. 

 « = 48° 17' 37"-6 

 n = 309° 27' 46" 

 i = 52° 29' 52"-3 

 log. 1/ = 8-591600 

 Meiiiorie delta Soc. degli Spectroseopisti Italiani, Oct. and Nov. 

 1873. — These numbers contain an interesting paper by P. Rosa, 

 assistant at the Observatory at Rome, on the variability of the 

 sun's diameter. He discusses the observations at Greenwich 

 and other places from the year 1750 to 1870, during which time 

 some 13,000 measurements of the solar diameter were made. 

 From these observations he has constructed curves showing the 

 variation of diameter, together with the variation in the number 

 of spots. The agreement of these two curves is not very strong, 

 but on his constructing secondary curves from every fourth year 

 of these primary curves, beginning with any year, the resemblance 

 becomes striking. There are also monthly curves given, showing 

 the mean variation in diameter of the sun for each month, taking 

 a mean of ten years for each curve. These show two maxima 

 in March and September, and two minima in January and June. 

 On examining the curve of variation in diameter, a marked 

 minimum occurs about the year 1792. The author sets forth a 

 theory to account for this variation, that since a comet, when at 

 its perihelion, throws off large quantities of matter, so the sun 

 whan at its periastre may throw off matter and become reduced 

 in, size, and if such is the case its periastre happened in 1792. — 

 G. Lorenzoni contributes papers on observations on the chromo- 

 sphere, and on observing contacts in eclipses of the sun with the 

 spectroscope. — G. de Lisa gives obsei-vations on solar spots in 

 September, October, and November 1873, made at I'alermo, 

 giving a mean of about ten spots a day. — Prof. Young gives a 

 note on the use of M. Rutherford's gratings in the place of prisms 

 ior the spectroscope. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, March 19. — On the Attractions of Magnets 

 and Electric Conductors, by George Gore, F.R.S. 



Being desirous of ascertaining whether in the case of two 

 parallel wires conveying electric currents the attractions and re- 

 pulsions were between the currents themselves or the substances 

 conveying them, and believing this question had not been pre- 

 viously settled, I made the following experiment : — 



I passed a powerful voltaic current through the thick copper 

 wire of a large electromagnet, and then divided it equally between 

 two vertical pieces of thin platinum wire of equal diameter and 

 length (about six or seven centimetres), so as to make them 

 equally white hot, the two wires being attached to two hori- 

 zontal cross wires of copper. 



On approaching the two vertical wires symmetrically towards 

 the vertical face of the one pole of the horizontally placed 

 magnet, and at equal distances from it, so that the two down- 

 ward currents in them might be equally acted upon by the 

 downward and upward portions respectively of the currents 

 which circulated round the magnet-pole, the one was strongly 

 bent towards and the other from the pole, as was, of course, 

 expected ; but not the least sign of alteration of relative tempe- 



