105 



mlttem in visibility, that which was opposite to the left hand 

 of the spectator being the most so. 



After 11 o'clock the appearance became more and more 

 obscure, until the cross was replaced by an obscure blur. The 

 paraselense also disappeared, while the halo, though diminished 

 in brightness, continued some time longer. 



June 9, 1845. 



CAPTAIN LARCOM, R. E., Vice-President, in the 

 Chair. 



James Claridge, Esq., Adolphus Cooke, Esq., Windham 

 Goold, Esq., Charles Croker King, M. D., and Charles Wye 

 Williams, Esq., were elected Members of the Academy. 



Mr. Richard Sharpe read a notice of a new electric clock, 

 on the principle of Mr. Wheatstone's telegraphic instruments. 



The Rev. Charles Graves made a further communication 

 relative to Algebraic Triplets, and their Geometric Inter- 

 pretation. 



Besides the system of algebraic triplets developed in former 

 communications to the Academy, Mr. Graves has conceived 

 another, which appears to admit of an interpretation in some 

 respects more closely analogous to Mr. Warren's geometrical 

 representation of imaginary quantities. 



As the symbol V' — I may be taken to indicate a rotation 

 in the plane of x from the axis of x to the axis of y, it seems 

 natural to conceive another symbol representing a rotation in 

 the plane of xz, from the axis of x to the axis of z. The re- 

 petition of either of these operations would reverse the direc- 

 tion of a right line originally placed on the axis of x : and 



VOL. in. I 



