34-8 Intelligence and Miscellajieous Aiticles. . 



Since the preceding matter was in tyjje, a copy of Professor Silli- 

 man's Journal of Science and Arts, for Januarj 1842, has arrived 

 from America, containing an article " On the Solar Eclipse of July 

 8, 1842 ' {civil time), from which the following is extracted, as me- 

 riting particular attention : — 



" As the approaching eclipse will excite gi'eat interest throughout 

 Europe, and especially in those places where it will be total, it is 

 earnestly hoped that particular attention will be paid by tiiose fa- 

 vourably situated, and in possession of suitable instruments, to the 

 determination of the correctness of a recent suggestion, that the 

 irregularities so frequently noticed at the second and third contacts 

 of nearly central eclipses, and at all the contacts of the transits of 

 Venus, may be seen or not at the pleasure of the observer, according 

 as the colour of the dark glass he ajiplies to his telescope is red or 

 green. These irregularities, as seen by many, have been minutely 

 described by Francis Baily, Esq. of London, in an article in the 

 tenth volume of the Memoirs of the Astronomical Society, although 

 it particularly relates to the appearances, observed by himself, in the 

 south part of Scotland, during the eclipse of May 15th, 1836, which 

 was annular there. Many of the appearances described by Mr. Baily 

 were seen through a red glass at the second and third contacts of 

 the eclipse of February 12th, 1831, which was annular in the south- 

 eastern part of the State. Shortly afterwards, however, it having 

 been ascertained that a double screen, composed of one light red and 

 one light green glass, would not only render the light of the sun very 

 pleasant to the eye, but would far better define the limbs, and would 

 sometimes even enable me to see a small spot, that was invisible 

 through the dark red^'alone, a screen of that kind was adapted to 

 the telescope, and was used for the partial eclipses of 1832 and 

 1836, and those that were central in 1S34 and 1838. Through this 

 screen no one of the irregularities described by Mr. Baily has ever 

 been perceived, although carefully looked for. Indeed, so remark- 

 able was the difference between the observed and expected appear- 

 ances of the sun's limbs at the second and third contacts at Beaufort, 

 S. C. on November 30th, 1834, that even then a suspicion was ex- 

 cited that the entire absence of all distortion or irregularity in the 

 cusps, just before and after the total obscuration, was to be attri- 

 buted to the colour of the screen, especially since other observers in 

 the vicinity of Beaufort saw through red screens many or most of the 

 usual phsenomena. This suspicion was strengthened by the obser- 

 vations on the large, but not central eclipse of May 1836 ; it was 

 therefore communicated to several of our astronomers, who paid 

 particular attention to it, at the formation and rupture of the ring 

 on September 18th, 1838. In Philadelphia and its vicinity there 

 were many observers, provided with telescopes of nearly equal optical 

 capacity, but protected by screens of different colours. The result 

 appears to be, that in every, or nearly every instance, in which the 

 red glass was used, many or all of the usual irregularities were seen, 

 whilst those observers who used yellow or green screens saw these 

 appearances either greatly modified or not at all. At Princeton, near 

 the northern boundary of the ring, two skilful astronomers, provided 



