OF THE SUN, JUNE 16, 1306. 257 



pass through the centre of the sun : — then B will represent the 

 point of the southern cusp. At about 10 h 53' the point of the 

 cusp appeared as in Fig. 3, the thread of light, a b, disappear- 

 ed from one end to the other, at the same instant, the point 

 of the cusp then appeared as in Fig. 4-. — In a very short time 

 the thread of light which connected b with the body of the 

 cusp disappeared, and left b visible for a number of seconds, 

 after it was detached from the other visible part of the sun. 

 The cusp then appeared very obtuse, as represented in Fig. 5 

 which was observed by those who were using the most indif- 

 ferent glasses. 



Those detached luminous points of the sun's limb, seemed 

 to retain their brilliancy, till the instant of their disappearance, 

 which it would appear should not have been the case, if the 

 moon was surrounded with an atmosphere: — those points par- 

 ticularly, which were formed by depressions in the moon's 

 limb, would have had their splendor somewhat diminished, 

 by the density of the atmosphere, if one existed :— but nothing 

 of the kind was observed. 



The sun's diameter was found by a great number of obser- 

 vations, made both on the day of the eclipse, and the day pre- 

 ceding, to be 5$^ divisions of the micrometer: — the deno- 

 minator of the fractional part of a division being constantly 

 50 the numerators only are entered in the observations, — 

 When the first measures were taken, a line joining the points 

 of the cusps passed nearly through the centre of the sun : — in 

 that situation it will easdy be seen that the distances must re- 

 main for a few minutes so nearly the same, that but little ad- 

 vantage can be drawn from the observations; on this account 

 I have only made out the results of twelve observations on each 

 side of the measure, taken at 10" 55' 27", which turns out 

 accidentally to be, not only the middle observation, but the 

 shortest observed distance between the points of the cusps: — 

 the first and three last observations, are therefore omitted in the 

 calculations. These observations may be so varied, as to fur- 

 nish a great number of results, because any two, however ta- 

 ken, on different sides of the apparent conjunction* may be 

 considered almost equivalent to the observation of an eclipse, 



