Mr. Caldecott on the Solar Eclipse of IMS, December 21. 313 



est imaginable quantity of being totally eclipsed here. The corona 

 was very faint and of a greenish-yellow colour, occasioned doubtless 

 by seeing it through a very thin film of smoke, for the total removal 

 of the darkening shade had not been provided for. It was never quite 

 dark, or too dark to read off the actinometer : Venus, Saturn, and 

 Arcturus were seen by the author's servants, who had been instructed 

 to watch for stars. Mr. Caldecott saw nothing of the luminous 

 protuberances noticed by Mr. Baily and Mr. Airy*, but the greatest 

 obscuration was so momentary in this eclipse, that there was no time 

 for the eye to give more than a glance round the disc before the sun 

 and moon were again separating, and strong light was restored. 

 Shortly after 9** a.m. the author took another set of altitudes of the 

 upper limb of the sun, and the appearances during the separation of 

 the two bodies were observed every few minutes, but nothing worthy 

 of remark was seen. The actinometer readings and the resulting 

 radiation are given in an accompanying table, together with some 

 occasional readings of a thermometer taken at irregular intervals du- 

 ring the progress of the eclipse. The impression on Mr. Caldecott's 

 mind is, that the beads are the effect of the incessantly varying re- 

 fraction of the atmosphere on the two limbs, causing each of them 

 to have an apparently dancing or bubbling motion, and thereby pro- 

 ducing the appearance of spots of light, with intermediate dark spaces 

 or bands, after the body of the sun is in reality covered by that of 

 the moon, just as a planet or bright star when dipping into the ho- 

 rizon is frequently seen on a fair, clear night at sea to disappear and 

 reappear repeatedly. This appearance of beads he believes to have 

 been observed hitherto only at the eastern and western limbs, and, 

 as these approach to and recede from each other gradually, the dark 

 spaces or lines are more distinct for the moment of their appearance 

 than in this case, where the limbs just grazed along each other, as it 

 were, and in which, therefore, the bright spots assumed more of the 

 form of globules, altering their shape, size, and position, as the two 

 bodies moved past each other, with inconceivable rapidity. 



The corrected observed time of the termination of the eclipse was 

 101^28">5P-5a.m. 



h m s ' 



The longitude of the place of observation is 5 3 4 East. 

 The latitude 11 44 38 North. 



III. Sextant Measures of the Sun at the Eclipse of the Sun on 

 the 21st December, 1843. By Captain Sir Edward Belcher, R.N. 

 Communicated by Captain Beaufort, R.N. 



The observations consist of nineteen measures of the breadth of 

 the illuminated portion of the sun during the progress of the eclipse. 

 The longitude of the place of observation was 124° 12' 30" east, the 

 latitude 24° 21' 20" north. 



IV. On a Graphical Method of Predicting Occultations. By J. I. 

 Waterston, Esq. Communicated by Captain Beaufort, R.N. 



The following is the author's account of his method : — 



" The following is a description of a graphical method of predicting 



* See Phil. Mag. S. 3. vol. xxii. p. 386, 391. 



