Mean Variation of the Magnetic Needle. 
0 1/1 
June 1821, 24 11 18 
1822, 24 9 55 
1823, 24 9 48 
Corrections. 
Part I., p. 145, 1 . 9, and p. 148, 1 . 12, for decipimenta, read dissepimenta. 
