500 Canadian Record of Science. 



cannot extend his collection much beyond this, unless indeed he takes 

 in some of those rare visitors from outer space —called meteorites — 

 which once in a while tumble down to the earth, usually with a bright 

 light and loud explosion." 



Chapter VIII., on the Determination of Minerals, gives some useful 

 advice, a little of which may be reproduced here : — 



"Confidence and hasty judgment," Dr. Dana tells us, "belong to 

 those who have little experience and a scanty knowledge of the diffi- 

 culties of the subject. 



"But, on the other hand, to recognize most of the minerals which 

 are likely to be collected on a mineralogical excursion, or to be obtained 

 by exchange with other collectors, is generally easy even for the 

 beginner, if he goes at the subject in the right way. 



" The best way, then, for one with a specimen of an unknown 

 mineral in hand, is to think of the common species first, and afterwards 

 of others which may suggest themselves, running over in mind, or by 

 reference to the book, the characters observed and those of the species 

 to which it is provisionally referred, but with care not to decide too 

 hastily, but to give each character full weight. Do not give the name 

 albite to a specimen of barite, either the tabular glassy crystals or the 

 white massive granular kind, because both species are often white 

 and also resemble each other in form, and overlook the fact that it is 

 much too heavy as well as too soft. Do not give the name beryl to a 

 crystal of apatite because it is a green hexagonal prism, and overlook 

 the fact that it is quite too hard. Finally, do not hesitate to confess 

 ignorance — that the experienced mineralogist is ever ready to do ; and 

 it is this fact that enables him from time to time to identify some rare 

 and interesting species, and perhaps occasionally one new to science." 



The chapters on the physical and chemical characters of minerals 

 are clear and to the point, and the descriptions of species, while neces- 

 sarily restricted, bring out well the essential characters of the minerals. 



The book has an attractive cover, is well printed, and admirably 

 illustrated. B. J. Harrington. 



Life and Rock : A Collection of Zoological and Geological 

 Essays. — By R. Lydekker, B.A. Cantab., F.Z.S. (Knowledge Series). 

 London, 1894. 



" Life and Rock," comprises a series of essays relating to zoological 

 and geological subjects, more especially to the former. Some of the 

 chapters deal with the natural history of certain animals ; others treat 

 of the interesting problems of evolution and development in a popular 

 style, aimed to reach those lovers of nature who are repelled by the 

 technical phraseology of scientific treatises. 



