51 



faint light between the cusps, and shortly afterwards a brush of 

 greater intensity, projecting from near the lower cusp. This pheno- 

 menon was not seen by Prof Alexander in the Fraunhofer with 

 green screen glass, till 61 seconds before the formation of the ring, 

 and then only as a luminous spot. This difference could not have 

 been the result of any oversight on the part of Prof. Alexander; as 

 Prof. Henry, immediately on seeing it, called out to Prof. Alexander, 

 and described its appearance. The optical capacity of the Fraun- 

 hofer is superior to that of the Dollond. Prof. Alexander is well 

 known for his nice observations of the annular eclipse of the 13th Feb- 

 ruary, 1831, and of the total eclipse of the 30th November, 1834. Its 

 explanation must be sought for in the nature of the rays of which 

 this arch and brush of light are composed ; rays absorbed by the 

 green screen glass, and transmitted by the red. The moon's limb 

 became brightly illuminated at 4ft 32m 53.28s. "An appearance, 

 similar to a row of beads, was regarded as the formation of the ring." 

 " The drops endured for a second or two." Expecting a longer dura- 

 tion of the ring, the attention of the observers was not directed to the 

 sun's limb at the instant of the rupture. The light succeeding the 

 rupture of the ring was visible in the Dollond telescope till 4ft 41 m 

 16.27s, (the minute uncertain, perhaps a minute earlier), having dis- 

 appeared several minutes earlier in the Fraunhofer refractor. 



No. 28. The beginning of the eclipse was observed by William 

 Cranch Bond, at his private Observatory, with a two feet Gregorian, 

 power 44; latitude 45° 19' 15", longitude 4ft 44m 17.29s west of 

 Greenwich, (or 0.69s in time west of Boston State House by Mr. 

 Paine's trigonometrical survey) as follows : — 



Beginning, 3ft 28m 10.90s mean time of place of observation. 

 End, lost by clouds. 



No. 29. The beginning was observed at 3ft 28m 11.6s at the 

 State House, Boston, by Mr. Borden, with a 3^ feet refractor. Clouds 

 prevented its observation at Cambridge. 



The Committee also reported the following observations of R. T. 

 Paine, Esq., on the occasion of his journey to Washington to observe 

 the eclipse. These were made with his sextant, constructed by Trough- 

 ton for the chronometrical survey of Massachusetts, and carefully 

 corrected by that artist for all sensible error of eccentricity; and 

 with three excellent chronometers used by Mr. Paine in the survey. 



