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XV. Intelligence and Miscellaneous Articles. 



POSTSCRIPT TO MR. T. G. BUNt's PENDULUM EXPERIMENTS. 



June 23. TOURING the last two or three days I have been making 

 ■^-^ some further experiments, with a view to ascertain 

 more nearly the rate of the apsidal motion, when the arc of vibration 

 becomes very small. Twelve experiments, averaging about 20 minutes 

 each, gave 11°'60 for the azimuthal horary motion, when the mean 

 length of the arc was 11 inches and the ellipticity +0*19 inch; 

 and seventeen similar experiments gave 11°*39 per hour, when the 

 ellipticity was —0' 17 inch. The mean length of arc, ellipticity, and 

 motion in azimuth, for each hour, are as follows : — 



On leaving the pendulum yesterday evening I gave it an impulse,* 

 intending to see what would be the motion of the plane during the 

 night. At 7^ 34"^ p.m. it was vibrating towards the division 1 70°'53, 

 the arc being 22 inches and the ellipticity — 0*04 inch. This 

 morning, at 9^* 30™, the plane of vibration cut the circle at 331° '80, 

 the ellipticity was about — O'Ol inch, and the arc 1*6 inch. The 

 mean hourly motion during the night had therefore been ll°-576. 



I stated in my former letter, that the motion of the plane of vi- 

 bration, when in proportion to the sine of the latitude of St. Nicholas 

 Tower, is 11°* 7309 per hour. This is true for an hour of sidereal 

 time only; for an hour of mean time, the amount will be 11°*763 

 nearly. 



ON THE TOTAL ECLIPSE OF THE APPROACHING 28tH OF JULYi^f 

 BY M. FAYE. '"*' 



A few days ago, through the politeness of Mr, Airy, I received a 

 remarkable tract published by a committee of the British Association 

 for the Advancement of Science, in conjunction with the astrono- 

 mers of Russia, for the purpose of making known the arrangements 

 which will be requisite for the complete observation of the approach- 

 ing eclipse. Since the Committee has done me the honour of direct- 



Phil, Mag. S. 1. Vol. 2. No. 8. July 1851. , G 



