ASTRONOMY. 295 



We are not aware that any complete observation of a comet on the 

 meridian at noonday has been made since the year 1744. The grand 

 comet in the early part of that year, first remarked by Kliukenberg 

 at Harlem on December 0, 1743, attained an extraordinary degree of 

 brilliancy towards the end of February. We find Bliss writing on 

 February 12 (O. S.) to Lord Macclesfield, who had fitted up an observa- 

 tory at Shirburn Castle, thus : " The comet appeared so very bright 

 last night, oqualiug the light of Venus, that Dr. Bradley agrees that 

 it may be seen on the meridian, and being engaged himself, has desired 

 me to request your lordship to try to observe it. The elements whicli 

 lie left at ShirBurn api)ear, to our last night's and former observations, 

 to give the j)lace true within 2' of longitude and latitude." As a mat- 

 ter of fact the comet was observed on the meridian near noon at Shir- 

 burn on the 28th and 2.0th of February, and at Greenwich on the 29th; 

 these observations will be found reduced in Mr. Hind's paper -on the 

 comet of 1744. {Astron. Nach., vol. xxvii.) 



Photometric observations of WelW Comet. — Exact photometric observa- 

 tions of comets have been rare; but Dr. IMuller, of Potsdam, has 

 succeeded in obtaining a good series of observations of Comet Wells 

 with a Zollner's photometer, attached to one of Steinheil's refractors. 

 Having found considerable difficulty in measuring the brightness of a 

 comet with this photometer, owing to the great diflerence in appearance 

 between the comet and the artificial stars, he removed the disk that 

 bore them and substituted an artificial nebula; and the observations 

 from April 21 to May 19, 1882, were conducted with this latter. But 

 as the brightness of the comet increased he reverted to the original 

 disk. Thus his observations form two series which are not exactly 

 comparable. The entire series of observations, which were obtained on 

 21 days, from April 21 to June C, showed that the comet increased in 

 brightness much more rapidly than was to be expected from theoretical 

 considerations and calculations, so that it must be concluded that a 

 very remarkable development of the comet's own light took place. The 

 time Avhen this growth of intensity commenced was in the latter half of 

 May, about the time that the bright lines of sodium were discovered in 

 the spectrum. The photometric observations by themselves would have 

 justified the conclusion that in the middle of May extraordinary changes 

 took place in the physical condition of the comet, and this conclusion 

 was thus fully confirmed by the revelations of the spectroscope. From 

 the comparision of the nucleus of the comet with the stars D. M. 49°, 

 ISTo. 3062, and D. M. 49°, ^o. 3059, it was found that the nucleus of the 

 comet was equal in brightness to a star of the third magnitude on 

 June 6, whilst on May 19 it only equaled one of the eighth or ninth. 



Daylight observations of comet 1882 a. — Prof. Julius Schmidt writes 

 to the Astronomische Nachrichten that on June, 10, atter 3 p. m., in an 

 except ioually clear sky at Athens, he observed the comet, though with 

 difficulty, in the G-foot reflector of that observatory. 



