July 24, 1879] 



NATURE 



307 



in the region of Luled. The red light was visible at different 

 places for periods varying from ten to thirty minutes, the light 

 streak of cloud from some minutes to seventy-five, the whole 

 phenomenon being visible from ten to 105 minutes. 



At places nearest to the locality of explosion and at some others 

 there was seen only the intensely luminous fire-ball, not the red 

 after-light, probably in part owing to the sky being cloudy, and 

 in part also for the ?ame reason as that which caused the dark 

 central field in the case of the Stalldalen meteor. 



The observations reported correspond so closely with the figures 

 calculated on the supposition that tlie explosion took place half 

 way between Lulea and Nederkalix at a height of 35 kilometres 

 above the surface of the earth, that this point of the meteor's path 

 may be considered as determined with considerable accuracy. 



All observers agree in thi*, that the red pillar of fire which 

 immediately after the explosion was seen at Upsala, Stockholm, 

 Fredrikshamn, St. Petersburg, &c., had at first the same direc- 

 tion as the meteor's spark -bestrewn path, but that the position of 

 the fire-pillar towards the close of the phenomenon underwent 

 change by its spreading out to a height in the atmosphere which 

 in the north of the Gulf of Bothnia was about three times as great 

 as that of the fireball proper. 



The tangent of the meteor's path at the place of fall had an 

 inclination to the horizon of about 25°. The radiation point 

 was situated somewhere in the constellation Orion. The meteor 

 appears to have been first seen at a height at which it was 

 beyond the earth's shadow, and illuminated by the sun. At 

 first it had the appearance of a bright star, but afterwards in- 

 creased rapidly in diameter till its apparent size was equal to 

 that of the sun or moon. From a comparison of numerous ob- 

 servation it appears that the meteor's luminous nucleus had a 

 diameter of 1,000 metres. 



The Lule4 meteor is interesting for the splendid light-pheno- 

 menon visible after its explosion, and particularly for the long 

 time it remained in the atmosphere without much change of 

 place. 



This light began immediately before the meteor exploded in 

 the region of LuleS, but it could not have been caused by com- 

 bustible substances thro\vn off in consequence of the explosion, as 

 in that case the red light ought to have spread itself from the place 

 of explosion about equally in all directions, and afterwards have 

 sunk down rapidly and gone out. Instead, this light was ex- 

 tended in the direction of the meteor's path, and it remained in 

 the sky for more tlian an hour. An approximate idea of its size 

 and height in the atmosphere is given by observations at Upsala 

 and Fredrikshamn: — 



Breadth of the red Approximate height 



luminous pillar. o£ the point. 



Upsala (2) 6 kilom. 125 kilom. 



Fredrikshamn ... 12 ,, 150 ,, 



The appearance of this light varied much. At some places 

 it resembled a pillar of equal breadth ("like a beam"), at others 

 it appeared as a red spot, from which a pillar of the same colour 

 descended to the horizon but disappeared sooner ; at others, 

 again, luminous rings were observed. After the light itself dis- 

 appeared, its position in the sky was marked for a long time by 

 numbers of "wool-like " clouds. 



Several observers remark that the red fire-pillar in question, 

 during the time that it remained visible in the sky, slowly as- 

 sumed a more vertical position, and then took the form of a 7 or 

 a reversed S. 



The LuleS meteor besides, like most other meteors, left behind 

 it for some moments a white luminous streak of fire in that part 

 of the sky through which it passed. This streak of fire clearly 

 arose from constituent parts of the fireball proper which had 

 been loosened by the resistance of the air, and remained behind. 



Tlie red light, on the other hand, appears to have had a dif- 

 ferent origin. It could not have consisted of small particles left 

 behind in the uppermost strata of the atmosphere, for they would 

 speedily have fallen down. The light rather appears to have 

 originated from new combustible or luminous material which 

 followed the nucleus of the meteor, and for the space of half an 

 hoiu: entered the atmosphere at nearly the same place. Tlie 

 Luled meteor was thus a true comctoid. 



It appears that the attraction of the earth and the retardation 

 caused by the resistance of the air gave the path of the dust, 

 causing the red light, a more parabolic form than that of the 

 meteor's nucleus, for a number of observers state that the red 

 pillar gradually raised itself from the slanting position of the 

 path of the meteor towards the vertical line. The direction of 

 flie meteor's train, as in the case of true comets, did not lie quite 



in the path of the meteor. The foot of the luminous pillar was 

 observed above Avasaxa at a height of about ico kilometres 

 when the nucleus exploded north of Lulei. After the dis- 

 appearance of the red light there remained white and wooUy 

 clouds, resembling light clouds illuminated by the sun. These 

 may have arisen from parts of the meteor which were directly 

 illuminated by the sun, and thus became visible when the 

 stronger light, caused by direct combustion, ceased. On April 

 29, in the latitude of Avasaxa, bodies at a greater height from 

 the surface of the earth than 76 kilometres are beyond the 

 shadow of the earth even at midnight. 



The meteor's light was at first white, then for a long time of 

 the same shade of red as the dawn, and near the close of the 

 phenomenon again white. The light probably arose from the 

 combustion of carbon and carburetted hydrogen, the products of 

 combustion, steam, carbonic acid, &c., absorbing part of the 

 rays of light, and giving the nucleus a reddish tinge. Towards 

 the close the gaseous envelope was dispersed, and the red colour 

 ceased a long while before the meteor finally disappeared. 

 Search was made for any meteorites or meteoric dust that might 

 have fallen, but none were found, although stones were seen to 

 fall to the ground "like rain" by two Lapp girls near Jock- 

 mock, and a Lapp reindeer-herd on the mountain Sarvikobbo 

 saw the ' ' stone-swarm " in question disappear in the forest 

 belcw him. 



SCIENTIFIC SERIALS 



Annalen der Physik und Chemie, No. 6. — In view of the 



considerable discrepancy between observation and theory with 



regard to the propagation of electricity, Herr Lorenz has been 



led to make fresh experiments (here described). In one method 



the telephone was used ; the other was a modification of 



Feddersen's jar-discharge method. Herr Lorenz shows that, in 



the case of iron telegraph lines, the magnetism of the iron must 



be considered. The electro-dynamic constant of unit length of 



2h 

 an overland telegraph wire is expressed by C = 2 log. - - + 2ir^, 



a 



where h denotes the height above the ground, a the radius of 

 the wire, and k the function of magnetisation. For unmagnetic 

 wires, the latter member falls away. Applying the formula to 

 Fizeau and Gounelle's experiments, and putting the function of 

 magnetisation of the iron wire = 10, we get the velocity xidooo 

 km., while that observed was 101710 km. The difference is 

 much less than by the ordinary reckoning, and maybe attributed, 

 the author thinks, to faults of insulation. — Studying the genera- 

 tion of the currents of a Gramme machine with regard to time 

 and resistance, Herr Herwig finds, inter alia, that at the com- 

 mencement a greater manifestation of force is obtained with 

 greater resistances ; but in later stages of development of the 

 current, the force increases more for smaller resistances. The 

 slow development of current with great resistances is shown by 

 the fact that with I3"4 Siemens' units, the full force possible was 

 not reached in four seconds. — Prof. CoUey concludes from 

 experiment, that the "polarisation of electrodes" in electro- 

 lytes is not to be attributed to dielectric polarisation of the 

 latter, but deserves the name just given. It is not denied, how- 

 ever, that the dielectric polarisation may exist, being completely 

 masked by the other. — Herr Settegaast makes some contribu- 

 tions to quantitative spectral analysis; his paper treating (i) of 

 distribution of a base between chromic acid and other acids ; 

 (2) of quantitative mode of determination of nitric acid, and (3) of 

 determination of phosphoric acid. — Among the remaining sub- 

 jects handled, we note the angle of polarisation of fuchsin 

 (Glan), application of the method of dimensions to proof of 

 physical propositions (Neesen), and the heat-conduction of 

 liquids with reference to currents arising from differences of 

 temperature (Oberbeck). 



The Quarterly yournal of Microscopical Science, July, contains : 

 — Notes on some of the reticularian rhizopoda of the Challenger 

 expedition, by H. U. Brady, F.R.S., with a plate. In this 

 second memoir several new and most interesting forms are de- 

 scribed and figured. The author mentions that he has failed to 

 detect in fresh specimens of Dcutylopora et uca, P. & J., the struc- 

 tures figured by M. Munier-Chalmas, which figures happcnto be 

 reproduced in this number of the Journal, as part of the minutes 

 of the Dublin Microscopical Club. — On the morphology of the 

 vertebrate olfactory organ, by A. M. Marshall, M.A., with two 

 plates.— On the brain of Blalta oricntalis, by E. T. Newton, 

 with two plates. — On the microphytes which have been found in 

 the blood and their relation to disease, by Dr. T. R. Lewis, with 



