50 Royal Society^ 



and about 48 seconds. At that calculatioPj the precise 

 number of seconds in 30,000 years is only 946707,840000 ; 

 or above 50 thousand millions less than one billion. So 

 that the number of seconds, which have passed since the 

 creation of the world, is considerably less than the fifth 

 part of one billion. In fact, it is only by some such con- 

 siderations that we can form any conception of numbers 8o 

 immense. 



** From the view we have taken of the Arabic notation, 

 it is plain that a cypher, wherever it occurs, increases ten- 

 fold the value of every figure standing on its left hand ; but 

 does not affect the value of the figures standing on its right 

 hand. It appears also that the several columns may be con- 

 ceived to be headed with their respective titles, as parcels 

 of a thousand each, of a hundred, of tens, &c." 



To the preceding extract, which may serve as a specimen 

 of the author's style, it is only necessary to add, that one 

 great merit of the work is, the lucid and full, yet perspi- 

 cuous, explanation of elementary principles, which it ex- 

 hibits, without departing from the rigidness of demonstra- 

 tion. In the detail the author has been happy in the 

 adaptation of examples to the doctrines they are proposed 

 to illustrate, and they are so contrived as to interest the 

 juvenile mind in the attainment of the results. 



To those who make themselves acquainted with the. 

 scientific principles of common arithmetic, the Elements 

 of Algebra offer no serious difficulty. Of these elements 

 the author has given such a view as may introduce the 

 student into that field of science, and enable him to mabe 

 further progress '* by the aid of the larger works extant on 

 the subject/' 



' . ' '■• I '■' -t 



Xi. Proceedings of Learned Societies, 



ROYAL SOCIETY. 



Jan. 14. JL HE Right Hon. the President in the chair. — A 

 paper detxiiling Experiments on Arsenic, Part II. by 

 William Lambe, M.D. was read. 



In this paper Dr. Lambe has continued his observations 

 ou arsenic. He has related the effects of potash, of am- 

 monia, and of lime, upon this metal, each of which sub- 

 stances has furnished new observations. 



By heating white oxide of arsenic with sub-carbonate of 

 potash, the oxide is divided into two pans : one portion is 

 acidified, the acid combining with the potash : another 



part 



