422 PHILOSOPHICAL TRANSACTIONS. [aNNO 1794. 



2dly, If A shall have died in any of the foregoing years, and b and c both died 

 in that year. 3dly, if b and A shall have both died in the foregoing years (e 

 dying last), and c died in that year. 4thly, If c and a shall have both died 

 in the foregoing years (c dying last), and b died in that year. From the frac- 

 tions expressing these several contingencies the value of the reversion will be 

 found, viz. by the application of the foregoing problems. 



Pkob. 6. — To find the value of a given sum payable on the death of c, pro- 

 vided A should be the first, b the 2d, and c the 3d that shall fail of the 3 lives a, 

 b, and c. This problem divides into several cases, which are considered sepa- 

 rately, and receive analytical solutions. 



XFIII. Observation of the Great Eclipse of the Sun of Sept. 5, 1793. Br/ 

 John Jerome Schroeter, Esq. p. 262. 



Having jjrepared my hand telescope, being a 7 -feet reflector, with a power 

 magnifying 50 times with great distinctness, and with a field that took in more 

 than the disc of the sun, I watched attentively for the first contact, but was pre- 

 vented by some intervening clouds : the first glimpse however I had was imme- 

 diately after the immersion, which took place at the north-west edge of the sun ; 

 and it was as yet so very trifling, that had it not been for the excellence of my 

 instruments I should hardly have perceived it ; and I am well assured that the 

 first contact did not take place above 4 seconds before this instant of time. This 

 observation was, according to true time, at lO*" 26™ 5Q\3 ; so that the first 

 contact must have been at lO*" 26'" 55^ The distance of the cusps I could not 

 observe. 



The end of the eclipse was observed with much more accuracy ; for though 

 the sun was at this time frequently covered by clouds of different densities, yet 

 by means of a variety of glasses, which I applied occasionally to the eye-glass of 

 my telescope, I was enabled to see distinctly the decreasing obscuration, which 

 during the last 3 seconds was scarcely perceptible, though certainly still existing, 

 the orb of the sun not being perfectly coinplete till after the expiration of the 

 last- mentioned interval, which ended at I*' 32"^ 54' true time. All these obser- 

 vations were made with the above-mentioned 7 -feet telescope, made by Professor 

 Schrader, magnifying 50 times. 



During the intermediate period of the eclipse, the atmosphere being tolerably 

 serene, I was enabled by the excellence of this telescope, and a large 1 3-feet 

 reflector, to make a very interesting observation, which led to some important 

 inferences. 1. All my telescopes, even the 3-feet achromatic, applied to my 

 quadrant, showed the globular body of the moon like a dusky grey orb floating 

 before the sun, its faint light becoming somewhat brighter towards the rim. 



2. Both myself and several other persons who were then with me, perceived 



