1820.] Col. Beaufoy on the late Solar Eclipse. 277 



Article V. 



Observations on the late Solar Eclipse. By Col. Beaufoy, F.R.S. 



(To Dr. Thomson.) 



MY UEAIl SIR, nushey Heath, Slanmorc, Sept. 8, 1820. 



I HAVE the pleasure to send you my observations on the late 

 solar eclipse ; and as they were made under very favourable 

 circumstances, the beginning and end may be relied on witiiin 

 a second of time. The period of the greatest obscuration cannot 

 pretend to the same accuracy. It was ascertained by measuring 

 the distance of the lunar horns with an eight inch Hadley's sex- 

 tant made by StanclifF, divided to 15 seconds, and mounted on a 

 stand. The magnifying power of the sextant's telescope was 12. 

 I remain, my dear Sir, yours very sincerely, 



Mark Bkaufoy. 



Latitude 51° 37' 44-3" N. ; Long, in time. West, 1' 20-93" 



Sept. 7, 1820. 



e , ^ r r^^gi""'"^: .• • • T '^o 'ir'l Apparent time 



Solar Echpse < Greatest obscuration. 1 o2 4o V at Bushev 

 LEnd 3 14 57 J ' "" 



Meteorological Table. 



Hour. Baroni. Therm. Hysrimi. Ther. in sun. Wiiiil. 



Remarks. 



The hmbs of the sun and moon were extremely well defined 

 from the commencement to the end ; the horns of the moon 

 were sharp, and terminated in a point. No occurrence took 

 place that denoted the appulse of the moon's limb towards the 

 sun's disc. At the beginning, the velocity of the v.'ind was 

 about ten miles per hour ; it died away at the greatest obscura- 

 tion, and afterwards freshened. The moon's edge was serrated, 

 with one protuberance larger than the rest, on her apparent upper 

 limb. No spots were visible on the sun. The magnetic needle 

 was not affected by any tremulous or libratory motion, but the 

 morning and noon variation were less than during the preceding- 

 days of the month. A sensation of cold was experienced at the 

 middle of the eclipse. A convex lens, four inches in diameter, 

 and 1 1 inches focal length, was fixed at one extremity of a frame 

 that had both a horizontal and vertical motion, and consequently 



