Revieivs — TJte Coal Resources of tJie BritisJi, Empire. 95 



searching over any maps that may be to hand. The same applies 

 to faults, which are quoted by the names by which they are known 

 in their respective coalfields, names often taken from places not 

 marked on any map of less scale than 6 inches to a mile, making 

 their identification often a matter of some considerable length ; and 

 this is especially the case in the regions where no recent geological 

 map has been published, since in these districts the fault lines and 

 boundary lines on the jiublished maps are frequently quite incorrect, 

 and do not serve as any guide to the modern reading of the structure. 

 With this criticism, however, we may say that the book is one of 

 great use both to students and to practical mining men, and one 

 which fills a deeply felt want. 



W. H. WiLCOCKSOX. 



Imperial Institute Monographs ox Mineral Eesources : 

 Coal. By J. H. Eonaldson, M.I.M.E., etc. pp. 166, with 

 maps and diagrams. London : John Murray. 1920. 6s. net. 



rpHIS monograph deals with the distribution of coal and the coal 

 -L resources within the British Empire. The subject is a very 

 large one, but the author has succeeded very well with his task, 

 which has entailed an enormous amount of compression. The 

 description of the coalfields is necessarily very brief, but the extent 

 of the fields, so far as proved, the age, quality, and average thickness 

 of the coals are stated, also the proved and probable resources of 

 each area are tabulated. Each section is illustrated by a map, 

 on which each coalfield mentioned in the text is clearly indicated 

 by numbers, so that reference from the text to the map and back 

 again can be readily made. These maps give a very good idea of 

 the extent and distribution of the coalfields in the Dominions and 

 the British Isles. Two graphs are given showing the coal outputs 

 of the various countries of the vforld between 1865 and 1916. It 

 is unfortunate that these are placed on opposite pages, for the 

 scale of the first, dealing with the three largest producing countries, 

 is only one-tenth of that of the second dealing with the countries of 

 smaller output, and the result is that any one picking the book up 

 casually might imagine that the output of Austria-Hungary was 

 equal to that of the United States until he began to look more care- 

 fully at the scales. The real value of a graph is that it shows 

 relationships of figures immediately to the eye, and it should not 

 be necessary to look carefully for scales. However, the book should 

 prove very useful for reference, particularly on account of its 

 handy size and the clearness of its maps. 



W. H. AViLCOCKSON. 



