i873«J Notices of Books. 411 



to say nothing of the discovery of electricity and magnetism by 

 the ancients, the peculiar smell observed in a room in which an 

 electrical machine is kept in action, was long ago observed, but 

 called the " smell of electricity," and thus left unexplained. 

 The sagacity of Schonbein led to the discovery that this is due 

 to the formation of ozone. 



We cannot for want of space follow our authors through the 

 consideration of the principle of repetition in experiment, agree- 

 ment, and difference, the use of mathematical theories, and the 

 evaluation of error by the method of least squares, all contained 

 in one valuable chapter of a still more valuable volume. We 

 have fulfilled our duty in presenting it to the notice of the 

 teacher, the taught, and the reading public : to the teacher, 

 because he will find in that which will silence the cry " there is 

 no good text-book of Natural Philosphy ; " to the student, because 

 it shows how he should be taught or teach himself; to the 

 reading public, because it will give a clear idea of the beauty 

 and exactitude of the logical method in science. 



Science Primers : Physical Geography. By Archibald Geikie, 

 LL.D.,F.R.S., Direaor of the Geological Survey of Scotland, 

 and Murchison Professor of Geology and Mineralogy in the 

 University of Edinburgh. London : Macmillan and Co. 1873. 

 This little work will be found of incalculable value to the ele- 

 mentary student. It will be alike interesting to the general 

 reader, as giving a pleasing description of the phenomena of air, 

 earth, and water. The author asks us to follow him in a country 

 ramble, and read the book of Nature unfolded to us, to learn 

 the relationship of the air we breathe and the earth upon which 

 we live, and to watch with attentive eyes the changes which are 

 continually taking place around us. The details are explained in 

 a simple and comprehensive manner, and throughout the book a 

 desire is evinced to impart knowledge which will be of practical 

 value. It is illustrated by several woodcuts. 



Physical Geography. By William Hughes, Professor of 



Geography in King's College, London, Author of " A Manual 



of Geography," &c. London : Longmans, Green, and Co. 



i873. 



This is a useful little school-book. It treats of the Earth's 



natural aspects, phenomena, and productions, in a simple and 



interesting manner. In the present day increased attention is 



given to the study of these natural phenomena, and this book 



will prove of material assistance to the elementary student. 



Teachers will do well to recommend it to their pupils. 



