NATURE 



389 



THURSDAY, AUGUST 26, 1897. 



OUR COAL RESOURCES. 

 Our Coal Resources at the Close of the Nineteenth Century. 

 By Edward Hull, LL.D., F.R.S. Pp. xii + 157. 

 (London : E. and Y. N. Spon, Ltd., 1897.) 



IT will be a matter of sincere regret to all mining 

 students to learn from the preface to this work that 

 when in 1895 ^^^ l^st copies of the fourth edition of Prof. 

 Hull's " Coalfields of Great Britain" were sold out, the 

 publisher decided not to issue a new edition. This want 

 of enterprise obliges students to content themselves with 

 perusing the well thumbed copies in our public libraries. 

 Fortunately, however, the author has now written a 

 supplementary volume dealing with investigations into 

 the coal resources of the British islands, and bringing 

 the statistical information contained in the original 

 volume up to date. 



The question of the duration of our coal supplies has 

 not lost any of its interest since the publication in i860 

 of the author's reassuring statistics, and since the issue 

 of the report of the Royal Commissioners in 1871. The 

 annual output of coal in this country, which when the 

 Commissioners first met together did not exceed a 

 hundred million tons, has now risen to nearly double 

 that quantity, and the process of exhaustion still con- 

 tinues. Clearly, therefore, the author is well advised in 

 regarding the close of the nineteenth century as a fitting 

 occasion for taking stock of the British coal resources 

 upon which so much of the commercial prosperity of 

 the Empire depends. In his estimates of the indi- 

 vidual coalfields of Great Britain, the figures of the 

 Royal Commission have been adopted, after making 

 deductions for quantities credited to seams under 

 two feet in thickness, which ought, in his opinion, 

 to have been omitted from the calculations of the 

 Commissioners. Modifications have also been necessary 

 in estimating quantities outside the visible coalfields in 

 areas concealed beneath the Permian and Triassic 

 formations. Moreover the quantity extracted from 1870 

 to 1895, and the estimated quantity from 1896 to 1899 

 have been deducted so as to give the resources available 

 at the end of the century. The total estimated quantity 

 of coal within a depth of 4000 feet remaining at the close 

 of the century is thus found to be 81,683,000,000 tons, 

 the quantity remaining in the visible coalfields of 

 Great Britain and in partially concealed areas being 

 58,275,700,000 tons, that in the entirely concealed 

 areas 23,253,000,000 tons, and that in Ireland 155,300,000 

 tons. Unfortunately the production of the Irish coal- 

 fields is too insignificant to have anything beyond a 

 local interest. The author points out, however, that in 

 County Tyrone there is a tract e.xtending to the borders 

 of Lough Neagh overspread by Triassic and Tertiary 

 strata under which a valuable coalfield may be supposed 

 to lie. 



In ten chapters the different English, Welsh and 

 Scottish coalfields are discussed in detail. With regard 

 to coal south of the Thames, the author takes a hopeful 

 view of the future of the Kent coalfield. It may now, he 

 says, be accepted as geologically certain that between 

 NO. 1452, VOL. 56] 



Dover and Bath there occurs a more or less interrupted 

 trough of coal measures of 150 miles in length and of a 

 breadth varying from two to four miles. An interesting 

 chapter is that devoted to the position of the various 

 coal areas as regards the magnitude of the output, 

 classified as progressive, stationary, or retrogressive- 

 In the last case this character is a certain sign of 

 approaching exhaustion. The author's classification is- 

 as follows : — 



I. Progressive Coal Areas. — i, South Wales and 

 Monmouthshire ; 2, North Midland district ; 3, Scottish 

 group ; 4, Lancashire and Cheshire group ; 5, Great 

 Northern district ; 6, Denbighshire ; 7, Warwickshire ; 

 8, Cumberland (slightly) ; 9, Leicestershire (slightly), 



II. Stationary Coal Areas. — i, Bristol and Somerset- 

 shire ; 2, Forest of Dean. 



III. Retrogressive Coal Areas. — i., South Stafford- 

 shire ; 2, Flintshire ; and 3, Coalbrook Dale. 



The last forty pages of the volume are devoted to at> 

 inquiry into the approximate limit of deep mining andl 

 to the production of foreign coalfields. A great many of 

 the difficulties which were formerly connected with the 

 sinking of deep shafts have now disappeared. The chief 

 impediments are the increase of temperature and the 

 increase of pressure. In discussing the former obstacle, 

 the author might have cited more recent observations 

 than those made in 1848 at the Dukinfield Colliery, and 

 in 1854 at Rose Bridge Colliery, Methods of determining 

 earth temperatures have greatly improved since those 

 dates ; and the results recently obtained at the Paru- 

 schowitz borehole (where observations made at a depth 

 of 6573 feet showed an increase in temperature of i^ F. 

 for every 62' i feet), and at numerous other boreholes and 

 mines, details of which were given in a paper read before 

 the Society of Arts last year by the writer of this notice, 

 afford more conclusive evidence of the depths at which 

 mining is possible. 



Throughout the work the author takes a highly 

 optimistic view of the future of British coal-mining. 

 Thus on p. 9 he says: "Notwithstanding the develop 

 ment of the coalfields of foreign countries, which has 

 been considerable during the last quarter of a century, 

 British coal, owing to its superior quality, still holds its 

 own." This view characterises the entire work, and the 

 growth of foreign competition is ignored. Yet statistics 

 show that whereas Great Britain in 1840 produced 75; 

 per cent, of the world's supply of coal, at the present 

 time it produces only 34 per cent. Atlantic liners no 

 longer carry coal from Great Britain for the return 

 journey ; they now take in American coal, and no less 

 than one and a half million tons of American coal were 

 thus consumed in 1895. The author rightly points out 

 that the condition of the iron manufacturing industries 

 has always exercised a most important influence on the 

 production of coal, so that a large demand for iron 

 draws with it a large demand for mineral fuel. He does 

 not tell us, however, that during the last twenty-five 

 years the world's production of pig-iron has increased 

 from twelve to twenty-six million tons ; but the share 

 taken by Great Britain has fallen from 48*8 per cent, to 

 29 per cent,, whilst that of the United States has increased 

 from 14-1 per cent, to 26*2 per cent,, that of Germany from 

 1 1 '4 per cent, to 21-4 per cent,, and that of Russia 



S 



