London Electrical Society. 



327 



were registered by a chronometer regulated to sidereal time, and its 

 rate determined by a mean of successive transits of the same star. 

 The true sidereal time and right ascensions were taken from the 

 list of moon- culminating stars, the list of 100 stars, and the list of 

 stars liable to occultation given in the Nautical Almanac ; and the 

 remainder computed by means of the Royal Astronomical Society's 

 constants. The moon's right ascension was determined by apply- 

 ing the mean error of the chronometer to the observed right ascen- 

 sion. 



Places of Bremicker's Comet, as determined with the Equatoreal 

 Telescope at Mr. Bishop's Observatory. By the Rev. W. R. Dawes. 



LONDON ELECTRICAL SOCIETY. 



Sept. 21, 1841. — The papers read at this meeting were, — 1st, 

 A letter from Mr. T. Pine to the Secretary, " On the Ripening or 

 Maturing, and Decline of Vegetation." Third communication. 



2nd. Notice of " The Effects of a Lightning Flash." By Mr. 

 William Trackelton. 



3rd. Notice of " A Test for Nitric Acid in the Sulphuric Acid 

 employed in exciting Voltaic Batteries." By the Hon. Secretary.' 



Dissolve some sulphate of indigo in distilled water, and add some 

 of the solution to the acid ; if, on the application of heat for a few 

 minutes, the blue colour disappears,'nitric acid is present. This test 

 was shown to the Secretary by Dr. Leeson, in the laboratory of St. 

 Thomas's Hospital, in order that it might be communicated to the 

 Society for the benefit of those who find their zinc consumed, and are 

 not aware of this as one of the causes. 



4th. Notice " On the Relative Powers of certain Diaphragm Vol- 

 taic Combinations," and on " A new Form for the negative Element 

 of Voltaic Arrangements." By the Hon. Secretary. 



