182 TokH Eclipsi of August 7, 1809. 



modify the phenomena. This apparatus was constructed 

 for the purpose of testing it. 



It may here be stated, that the color of the glass had no 

 appreciable effect on the character of the phenomena. 



For the observations during totality no colored glass was 

 used. 



For regulating the aperture of the objective, holes of 

 one, two, three and four inches in diameter were cut in a 

 disk of thick card board. This was firmly screwed to a 

 block and made to revolve in front of the objective, by 

 means of a hand rod attached to the side of the telescope 

 tube. A spring dog, dropping in a notch, always brought 

 the opening over the centre of the objective. 



The telescope was equatorially mounted with hand rods 

 for giving slow motion in right ascension and declination. 

 ' A day or two previous to the eclipse, three posts were 

 firmly set in the ground for the observing stand. The 

 telescope was brought in the meridian and appropriately 

 adjusted for the latitude of the place, by observations on 

 the sun, made some time previous to the beginning of 

 the eclipse. 



The eye-piece used during the eclipse gave a power of 44. 



The Weather. 



The night preceding the day of the eclipse was one of 

 unusual anxiety to the observers, from the tact, that about 

 six o'clock it began to rain, and continued almost without 

 intermission until 11 P. m. In order to learn the worst we 

 went to the telegraph office and asked for weather reports 

 from west and east. At nearly all the stations from which 

 reports were received, extending from Omaha to Cincin- 

 nati, it was rainy or cloudy. These reports led us to 

 expect a storm extending over a large area of territory. 

 And it was presumed that it would be a day or two in 



