Sept. 8, 1881] 



NATURE 



431 



nucleus and circular coma. The tail wa>; to be ^een, l.ut was from the nucleus in front fall back to form the tail or a brigh 

 quite faint, and as before was less at the bx«e than the width of margin to it. These, as far as I have seen, have been absent. 



Guildown, August 31 J. Rand Capron 



Coir.et /; 1881 

 M. Ch. Fievez, the Astronomer adjoint at the Royal Obser- 

 vatorv-, Brussels, has been gocd enough to send me a copy of his 

 note on the analysis of the light of this comet, made w ith the 

 15-inch Merz-Cooke equatorial, provi>ionally installed at the 

 Avenue Cortenberg. The polariscopic observations demon-trate 

 that the polarisation of the nucleus was -trong (tres nette et bien 

 accentuee), while that of the tail was very weak. The-e observa- 

 tions were made at several days interval, fi-om iih. till midnight. 

 Sky polarisation was scarcely sensible. The spectroscopic obser- 

 vations proved the spectnim of the comet to consist of four bands 

 of intensity in the follow ing order : green, blue, violet, and 

 yellow, with wave-lengths 5160, 4780, 42CO (about), and 5620. 

 The original appearance of these bands was modified as the 

 comet receded from the sun, their edges towards the red then 

 becoming more and more defined. The nucleus presented a 

 brilliant continuous spectrum, in which however the Fraunhofer 

 lines were not recognised. The concluMons arrived at liy M. 

 Fievez were as follows : — That a great part of the light of the 

 comet was inherent to it, while the other part was reflected solar 

 light. That the strong polarisation of the nucleus indicated a 

 marked state of condensation of the matter composing it. That 

 the spectrum differed little from that of other comets. Lastly, 

 that the marked modifications in the brilliancy of the continuoiis 

 spectrum, and in the appearance of the spectrum bands indicated 

 a progressive diminution in the comet's temperature. The chief 

 interest in the above observations attaches to the feeble polarisa- 

 tion detected in the tail as compared with that found by Prof. A. 

 W. Wright and Mr. Cowper Kanyard, and in the absence of the 

 Fraunhofer lines, which were measured by Dr. N. de Konkolv, 

 and also photographed by Pr. Huggins. Whence, we mav ask, 

 arises the divergence of conclusions arrived at by M. Fievez and 

 Prof. Wright respectively, the one considering that the principal 

 part of the comet's light is from itself, the other that it is reflected 

 sunlight, and why were the Fraunhofer lines seen in the one case, 

 and not in the other? The answer lies, I think, not with the 

 instruments employed, but rather in the interoting probability of 

 change in the comet's structure or condition during the time c f 

 its examination. A comparison of the many observations re- 

 corded during its stay w ith us may possibly lead to important 

 discoveries in this direction. I am much interested to see that 

 Prof. C. A. Young infonns us that the green band was seen by 

 obsen-ers at Princeton split up into fine sharp lines coinciding 

 with those seen in the flame spectrum, ai^result to be expected, 

 but hitherto not attained. " J. Kand Capron 



Guildown, September 3 



The comet at present vi.sible was examined by me with the 

 spectroscope on the SJ-inch refractor on Saturday evening, 

 August 27. The three principal hydrocarbon bands were plainly 

 visible, the central one being the brightest, and on comparing 

 them with the spectrum of a spirit-lamp flame the coincidence t f 

 the least refrangible sides of the bands in the two s]:ectra was 

 sensibly complete. The nucleus gave a narrow continuous spec- 

 trum, and I could see no trace of such a spectrum except from 

 that point. I could see no 01 her band in the spectrum except 

 the three above mentioned, but the proximity of the comet to the 

 horizon may have something to do with this. 



George M. Seabroke 



Temple Observatory, Rugby, August 29 



A Pink Rainbow 



I srE.NT Sunday, August 21, at Mr. Tennyson's house. Aid- 

 worth, near Haslemere. The house stands on an elevated ledge 

 of the Blaclidown range, looking over the Weald towards the 

 Brighton Downs, between east and south-east. Abcut sunset 

 the deep red of the south-eastern sky attracted our attention, and 

 ■while we were looking at it w'e saw stretching across it a well- 

 marked rainbow, but of a uniform red or pink colour, which 

 Mrs. Tennyson compares, in a note I have just had from her, to 

 a " pink postage-stamp " — not the one now in use, but the last 

 discarded one. This was seen distinctly by Mrs. Teimyson, Mr. 

 Hallam Tennyson, and myself for, I think, more than a minute. 

 Mr. Hallam w ent to call his father, who was in another room, 



Sketch of Schaeberle 



h. 40m. in &' Co' ke equatorial. 



the coma. Dr. de Konkoly I see has examined the spectrum of 

 this comet, and found it a faint continuous one, with three 

 tolerably bright line', at follow ing positions : — 



I. 5601 it 2-5 

 II. 5161 ± 09 

 III. 4753 ± 0-6 



Estimated 

 brightness. 



0-4 



fO 



0-S 



August 28. Sh. jB, 



The appearance of this comet throughout has been peculiarly 

 distinguished from that class in which jets of light streaming 



