Feb. 15, 1872] 



NATURE 



307 



the Northampton iron district, are shown in the former ; 

 nor have the auriferous deposits of Central America or 

 British Columbia been indicated on the latter map. 



In a work intended for the general British public, the 

 temperature, when alluded to, should preferably have been 

 stated in degrees of Fahrenheit's thermometer, since, al- 



though the scale of Celsius or centigrade is often made use 

 of by men of science here, it will not be at all familiar to 

 the majority of the readers of Dr. Hartwig's book, which 

 it is to be hoped will have a very extended circulation. 

 -Sever.al errors in the text might also be pointed out — as, 

 for example, calling the usual Cornish ore or copper 



INIlIAM ROCK-CIT TEMPLE : I'ORCII OF THE CIIAn VA CAVE TEMPLE, AJUNTA 



pyrites a bisulphuret of copper ; titanium is stated to be a 

 metal of a copper red colour, &c. ; but when the great 

 extent of scientific ground over which the author travels 

 in this book is taken into consideration, some allowance 

 must be made, and it must' fairly be admitted that the 

 work, as a whole, is singularly free from serious errors. 



and wc would recommend it strongly, in the belief that 

 from its at once easy entertaining and instructive style, 

 it will be sure to interest many in the study of these 

 natur.al phenomena, to whom the vei7 name of Science is 

 at present associated with all that is dry and uninviting. 

 ^ D. F. 



