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XLV1. Notices respecting New Books. 



Results of Astronomical Observations wade during the years 1834, 

 1835, 1836, 1837, 1838, at the Cape of Good Hope; being the 

 Completion of a Telescopic Survey of the whole Surface of the visible 

 Heavens, commenced in 1825. By Sir John F. W. Herschel, 

 Bart., K.H., %c. 8>c. London: Smith, Elder and Co. 1S47. (Fifth 

 and concluding notice.) 



Chap. V. Observatio?is of H alley's Comet, with Remarks on its phy- 

 sical condition, and that of Comets in general. 



ri^FIE comet was first observed at the Royal Observatory at the 

 JL Cape on the morning of the 1st of September (1835), but it was 

 not before the 28th of October that Sir John Herschel obtained a 

 view of it. About the end of March, previously, he had carefully but 

 without success examined the places set down in M. llumker's ephe- 

 meris, and the whole adjacent region of the heaven ; nor was he 

 more fortunate when he resumed the search about the end of August, 

 by sweeping over the places given in the Nautical Almanac for that 

 year. On these occasions his efforts were uniformly bafHed by a drift 

 of light vapour hurried rapidly along by the south-east wind of the 

 season, but constantly forming anew nearly over the spot to which 

 the telescope was directed. At length, despairing of success at home, 

 and impatient of repeated disappointments, he dismounted the equa- 

 torial telescope, and having constructed for it a temporary stand, 

 transported it to a station on the Cape Flats, five or six miles to the 

 eastward of Feldhausen, where he was sheltered by a range of low 

 sand-hills from the violence of the wind, and freed by distance from 

 the obstruction produced by the Table Mountain with its superposed 

 mass of cloud. The instrument was erected about sunset on the 

 28th of October, and before the termination of the twilight he had 

 obtained an excellent view of the comet. 



The appearance of the comet in the 7-foot achromatic on this night 

 was " that of a nebula very suddenly and highly condensed in the 

 centre, to so great a degree indeed that I could not have ventured from 

 this observation alone to have denied the existence of a solid nucleus. 

 No phase, however, was perceptible on that central mass which might 

 have been so regarded. Neither was any other remarkable pecu- 

 liarity about the head, nucleus, or tail, noticed on this occasion." 

 On the following evening, which proved very clear at Feldhausen, 

 the 20-foot reflector, armed with an excellent mirror recently and 

 brilliantly polished for the purpose, was brought to bear on the 

 comet. " Under these circumstances its appearance was most sin- 

 gular Its nucleus, small, bright, and highly condensed, was 



shielded or capped on the side next the sun by a vivid but narrow 

 crescent of nebulous light, the front of which presented an outline 

 nearly circular, having an amplitude of somewhat more than 90° 

 from horn to horn." Within this was the nucleus, the horns of the 

 crescent extending a good way behind it on either side. " The 

 nucleus was decidedly not planetary, and as decidedly exhibited no 



