26 



NATURE 



[May 8, 1890 



The question of the spontaneous ignition of coal 

 scarcely meets with the treatment which its importance 

 merits, and no reference is made to the work of the Royal 

 Commission appointed in 1875 at the instigation of the 

 Board of Trade and the Committee of Lloyd's to inquire 

 into this subject. Many hundreds of vessels have without 

 doubt been lost by the spontaneous ignition of coal 

 cargoes, and there is a general belief that, with the con- 

 siderable increase of temperature in steam-ships due to 

 the introduction of high-pressure boilers and triple- 

 expansion engines, the liability to spontaneous firing in 

 the coal-bunkers is greatly augmented. The old idea of 

 Berzelius, that the tendency to spontaneous ignition was 

 mainly due to the presence of readily-oxidizable pyrites 

 is now exploded. The experiments of Richters, Durand, 

 and, in quite recent times, of Prof. Vivian Lewes, have 

 shown that this substance has quite a subordinate effect. 

 The cause is rather to be ascribed to the effect of ab- 

 sorbed or occluded oxygen upon finely-divided carbon- 

 aceous matter, e.g. dust or fine slack. The authors are 

 also of this opinion, and state that the only method of 

 preventing fire from such a cause is to keep the tempera- 

 ture of the mass of coal as low as possible by means of 

 thorough ventilation by currents of air. In a paper 

 recently read before the Institution of Naval Architects, 

 in which this question is discussed, Prof. Lewes comes 

 to the conclusion that this so-called ventilation is un- 

 doubtedly one of the most prolific causes of spontaneous 

 ignition, and he instances the cases of the four colliers, 

 Euxine, Oliver- Cromwell., Calcutta., and Corah., which 

 were loaded at Newcastle under the same tips, at the 

 same time, with the same coal, from the same seam. 

 The first three were bound for Aden, and were all 

 ventilated. The Corah was bound for Bombay, and was 

 not ventilated. The three thoroughly ventilated ships 

 were totally lost from spontaneous ignition of their cargo, 

 whilst the Corah reached Bombay in safety.' Prof. Lewes | 

 points out that for ventilation to do any good, cool air | 

 would have to sweep continuously and freely through j 

 every part of the cargo, a condition impossible to attain, 

 whilst anything short of that only increases the danger, 

 the ordinary methods of ventilation supplying about the 

 right amount of air to create the maximum amount of 

 heating. A steam coal absorbs twice its bulk of oxygen, 

 and takes about ten days to do it under favourable con- 

 ditions, and it is this oxygen which in the next phase of 

 the action enters into chemical combination and causes 

 the serious heating. 



One very remarkable change which is slowly making 

 its way in this country is seen in the more extensive 

 adoption of coal-washing machinery. Coal-washing 

 machines have long been in use in Germany, France, 

 and Belgium, and the exigencies of our iron manufacture 

 are gradually necessitating their introduction in Great 

 Britain, although the process has not yet reached the 

 same degree of perfection as on the Continent. The 

 effect of washing is to free the coal from pyrites and other 

 mineral impurities. Of course it is only under special 

 conditions that it can pay to subject the coal of this 

 country to this process, but there is no doubt that as 

 soon as the price of coal touches a certain point many 

 coals which are practically unsaleable at present will be 

 so treated. The authors describe a number of the more 



important coal-washing machines, and give details of 

 their duty and cost. 



The question of coking and coke-ovens naturally comes- 

 in for a very considerable share of attention, and practi- 

 cally all the more important methods are described and 

 fairly well illustrated, and the general nature of the tars 

 yielded by the various kinds of ovens is set forth, mainly 

 on the authority of Mr. Watson Smith. One of the most 

 valuable features in the work is the account given of the 

 methods of using Hquid fuel, and of the results obtained 

 on various railways (principally Russian) and with various 

 types of marine and stationary engines. The principles 

 of domestic heating by solid and gaseous fuel, and relative 

 efficiency of the various forms of open and closed grates 

 and of gas stoves, are carefully stated, and considerable 

 space is given to an examination of the modes of warming 

 public buildings. 



Analyses of boiler performances, and of the results 

 obtained by mechanical stokers and by the application 

 of gas-firing to boilers, methods of evaporation, with 

 special reference to multiple effect apparatus, occupy a 

 large portion of the section devoted to fuel in its applica- 

 tions to vaporization and evaporation ; and the concluding 

 portions of the book are occupied by descriptions of 

 special forms of kilns and furnaces. 



The work is admirably printed, and on the whole well 

 illustrated, and, what is very important in a book which 

 is rnainly a work of reference, it is furnished with an 

 excellent index. T. E. Thorpe. 



THE SELKIRK RANGE. 

 Among the Selkirk Glaciers ; being the Account of a 

 Rough Survey in the Rocky Mountain Regions of 

 British Columbia. By William Spotswood Green, 

 M.A., F.R.G.S. (London : Macmillan and Co., 1890.) 

 '"T^HE Canadian Pacific Railway, after crossing the 

 -L watershed of the Rocky Mountains by the Hector 

 Pass, descends for some four thousand feet into the valley 

 of the Columbia River. This, for a hundred and seventy 

 miles, flows in a northerly direction, parallel with the 

 crest of the range. Then, after a great sweep to the 

 west, it flows southward, parallel to its former course, 

 till it receives the Kootenay, the head waters of which 

 rise only a mile and a half away from its own. The 

 mountain-tract insulated by these rivers is called the 

 Selkirk Mountains. It lies roughly parallel with the 

 Rockies, and yet further west are the Gold Range and 

 the Cascades. Thus the railway traverses a mountain 

 region until the valley of the Frazer River, by which it 

 finally emerges, begins to broaden out towards the sea. 

 It is, to use Mr. Green's words, " a region of vast ravines 

 and wide valleys, whose sides, when not bare rock pre- 

 cipices, are clad in sombre forests, through which vvild 

 mountain torrents rush from glacier sources to placid 

 lakes, where, after resting for a while and reflecting the 

 hoary cedars and hemlocks, they issue forth as great 

 rivers, and with swift current hurry on to lose themselves 

 in the Pacific." 



Though the peaks of the Selkirks look down upon the 

 railway, their recesses, before Mr. Green's visit, were still 

 almost unknown. The reason is not difficult to discover. 

 The forests which clothe their lower slopes are unusually 



