428 ' NATURAL SCIENCE. Dec. 



guide-book to its collections that has appeared. As in its well-known 

 predecessor, " The Study of Minerals," Mr. Fletcher has struck out 

 an entirely original line. Those who expect to find in this book 

 merely the cheapest text-book of petrology that they can purchase to 

 prepare themselves for some elementary examination, or even to give 

 themselves a sound knowledge of the necessary facts and figures of 

 the science, will be disappointed. Shortly to characterise the plan 

 of the book, we should say that it provided an introduction to the 

 methods of all science, especially to those departments of science that 

 concern themselves with the orderly arrangement or classification of 

 things or facts, and that the study of rocks was brought in rather as 

 an illustration of scientific methods than as the principal aim of the 

 book. Perhaps this would be going a httle too far, for there 

 can be no doubt that whosoever chooses to master this little 

 book will also have gained no inconsiderable acquaintance with 

 the facts and principles of petrology. Roughly put, the author's 

 method in this guide is to set before the student a mis- 

 cellaneous assortment of rocks, and to ask him to classify 

 them. The incorrectness and impracticability of the classifications 

 that at first suggest themselves from such superficial characters as 

 colour, texture, or weight is exposed, and the student is then initiated 

 into the various means of investigating the inner structure, the 

 affinities, and the modes of origin of rocks, and so has placed before 

 him — clear to his understanding, though as yet unattainable — the 

 ultimate goal of a natural classification. Although the book is of 

 interest and even of value when taken by itself, yet its real worth will 

 not be apparent until it can be read in connection with the splendid 

 series of teaching specimens that the Department is gradually 

 accumulating and now beginning to arrange in the table-cases 

 adjoining those that contain the series introductory to the study of 

 minerals. The book is in fact what it professes to be — a Museum 

 Guide. Not indeed a description of exhibited specimens, or a barren 

 list of more obscure treasures, but a book that should enable every 

 intelligent person to proceed for himself to the true appreciation of 

 the contents of one section of our great Museum. 



For those who wish to acquire knowledge, the British Museum is 

 fast becoming more than a mere storehouse, and it will be to the teaching 

 collections more than all else that the growth of the scientific 

 collections will be due in the future. We congratulate Mr. Fletcher 

 and his assistants, Messrs. Miers, Prior, and Spencer, on the 

 thoroughly practical arrangement of the collections under their 



charge. 



The Geology of Ireland. 



Guide to the Collections of Rocks and Fossils belonging to the Geo- 

 logical SuRVEV OF Ireland, arranged in Room HIE. of the Museum of 

 Science and Art, Dublin. By A. McHenry, M.R.I. A., and W. W. Watts. 

 M.A., F.G.S. Dublin (for her Majesty's Stationery Office) ; Alexander Thorn 

 and Co. Price gd. 



Despite the publications of the Mineral Department of the British 

 Museum, fraught with such originality and freshness, and the 

 admirable treatises on art issued under the auspices of the South 

 Kensington Museum, it appears that there is still room for surprises 

 among official handbooks. Messrs. McHenry and Watts, in place of 

 a dry catalogue, have produced a manual of the Geology of Ireland 

 which will be even more valuable to those engaged in research than 

 to the ordinary visitors in the museum. The rocks collected by the 



