Notices respecting New Books. ' ^^^^^w^*^*^ | 



be expected, is an infinite series, symmetrical wixk respect to a 

 and b, and convergent for all possible values of those quantities. 

 The time of revolution (that is, the interval between two suc- 

 cessive arrivals of the pendulum-ball at the same apse) in terms 

 of a, b and /, is equal to 



V ^1/^ 16/2 ^ 1024/4 +^c.j-. 



The demonstration of these expressions, although not long, 

 might occupy more space than I can venture to claim. 

 I am. Gentlemen, 



Yours, &c.. 

 Trinity College, Cambridge, A. Thacker. 



Oct. 9, 1851. 



LXIII. Notices respecting New Books. 



The Ethnology of the British Colonies and Dependencies. By R. G. 

 Latham, M.D., F.R.S. 8fC. John Van Voorst, Paternoster Row. 

 1851. 



Man and his Migrations. By R. G. Latham, M.D., F.R.S. 8^c. John 

 Van Voorst. 1851. 



ETHNOLOGY, or the science of races, has for its objects the con- 

 sideration of the physical, mental, and moral characteristics of the 

 different races of men, their physiological and philological affinity, 

 and the question of their descent from one or more sources of origin. 

 The mere statement of these objects sufficiently indicates the com- 

 prehensive nature of the science, and the difficulties opposed to a 

 satisfactory solution of the problems which it involves. Not only 

 must the living characters of races be faithfully observed and com- 

 pared, and the influence of intermixture taken into consideration, 

 but the footsteps of each must be tracked along * the sands of time ;' 

 and where history ceases, and the mist of ages obscures their course 

 and movements, the aid of philology and archaeology must be in- 

 voked, and through these, if possible, their probable affinities and 

 origin be determined. Man must be considered also in relation to 

 the earth which he inhabits, and the question entertained, whether 

 the influences in operation on its surface afford a clue to the different 

 phases under which he exhibits himself in various regions. Hence 

 a moderate acquaintance with physical geography is indispensable. 

 Notwithstanding the varied nature of the qualifying studies, and the 

 faint hope of attaining by scientific research only to any definite 

 conclusion as to the specific unity or diversity of human races, the 

 science has of late years been prosecuted with considerable energy 

 in this country, as well as on the continent and in America. The 

 characteristic features of existing races have been accurately deli- 

 Phil Mag. S. 4, Vol. 2. No. 12. Nov. 1851. 2 F 



