264 The Irish Nahiralist. [November, 



geology ? We all know that we have to go back to the beginning with 

 our 3-ounger geological pupils ; but no opportunity should be thrown 

 away of enforcing the truth that all knowledge of the attractive " natural " 

 sciences must be founded on the accurate work of chemical and physical 

 laboratories. So long as the dubious adventures of a past mythology 

 are taught in secondary schools, while the fundamental laws of God's 

 world round us are left untaught, so long must we go on repeating that 

 " popular science " in the highest sense, is an impossibility in the British 

 Isles. 



Prof. Watts, like others before him, makes the best of a bad business 

 — and makes, indeed, a very attractive 1)est of it. We should have 

 preferred to throw Chapter II. (on the "Study of. a piece of stone ") and 

 Chapter X. (on "Minerals") into juxtaposition ; but that might have 

 deterred some readers from going further with the work. As it is, we 

 find between these chapters a good deal of information based upon 

 outdoor observation. The treatment of river-deposits, and, later, of the 

 origin of river-courses (pp. 311, &c.), seems to us a good example of the 

 scientific and thoughtful character of the book. 



If we add a few notes for the second edition, it is in the sure know- 

 ledge that it will soon be called for. On p. 54 we should like a defini- 

 tion of the term roche moutonnee — and the correct explanation of it, as 

 derived from the frizzly surface of wool. On p. 119, the so-called '' rare'' 

 elements are said to be uncommon in rocks. Should we not now-a-days 

 regard the word " rare" as referring to their distribution in very minute 

 quantities, rather than to their absence } On p. 120, the term "acid" is 

 used in a sense not always sanctioned by modern chemistry. On p. 128, 

 the plane of composition in twin-forms should, we think, have been left 

 unnoticed, if it had to be styled a " divisional plane," without further 

 explanation ; it would surely become confused with cleavage. On p. 122, 

 the tetragonal prism is got by elongation of a cube, without note as to 

 the difference in the position of the lines selected as lateral axes. On p. 

 172, '* Tachylite," for "tachylyte." with an erroneous derivation, appears 

 — as it does in almost every work, despite the protests of twenty years. 

 On p. 190, the quartz, felspar, and mica of gneiss, are said to occur in 

 alternate layers ; this, again, is a very common statement, but is quite at 

 variance with fact. The proportions of the constituents vary enormously 

 in different layers of gneiss ; but the layers consist of different types of 

 rock, rather than of distinct minerals. On p. 210, the Lower Cambrian 

 corals of America are overlooked. On p. 249, the position of the 

 siphuncle might have been made the important point in Clymenia, which 

 otherwise might fall in with the Goniatites. 



These are the trifling things that we have dropped on in this capital 



little book. The author's friends and readers will be glad to know that 



he has again a wide field open to him in his new teaching duties in the 



nucleus of the Midland University. 



G. A. J. C. 



