490 Coal Washing. [Oct., 



represent nearly the whole manufacture of it in this country. By 

 recent improvements it is now possible to burn small coal in boiler 

 furnaces, but by far the greatest portion of washed coal is converted 

 into coke, for which purpose it is specially adapted, and at most 

 large collieries in the country there may now be seen a coal-washing 

 machine and ranges of cokeing ovens as part of the indispensable 

 plant of the coUiery proprietor. 



About sixteen years ago a Mr. Morrison first introduced into 

 this country a coal-washing machine fi'om France, and having 

 obtained certain concessions from some of the north-country coal- 

 owners, he proceeded to set the apparatus to work, and soon became 

 celebrated for the superior quality of the coke manufactured by 

 him. It was, however, some years before the principle of coal 

 washing became at all general, and for some time Mr. Morrison 

 was the only person to carry it into practice. Gradually, however, 

 the process was taken up, first by one, and then by another, until 

 a washing machine has now become almost as necessary an adjunct 

 to a colliery as a j)umping engine. 



Very little alteration appears to have been hitherto made in the 

 general principles of the fii'st coal- washing machine introduced into 

 this country, but alterations in detail have materially conduced to 

 its greater efficiency and economy in working. As in the case of 

 most other useful inventions, all sorts of modifications have been 

 from time to time suggested, but few appear to have sufiiciently 

 recommended themselves on their own merits as to obtain any 

 success. In all cases, excepting where only slack is washed, the 

 coal has first to be broken up small, in order to prepare it for 

 the washing machine. The means generally employed for separating 

 the impurities from coal is gravitation, the mineral to be washed 

 being thrown into water, when the earthy matters sink to the 

 bottom, whilst the coal, being the lighter, forms an upper layer 

 which is easily removed. 



Numberless contrivances have been proposed for more readily 

 effecting this disposition of strata in the washing machine, but, 

 with the exception of those which we shall presently notice, few 

 have come into general adoption ; and whilst many other plans 

 have been projected for removing the impurities from coals, those 

 in which water is employed, either in a runnuig stream or in 

 agitation, as will be presently described, alone appear to have been 

 brought into practical use. In order to give a better understanding 

 of how the last-named machines effect this scpai'ation, we shall first 

 describe them more in detail, and then proceed to give some further 

 particulars regarding the methods requisite to prevent any un- 

 necessary waste of fuel ; since, if care be not taken, much coal is 

 liable to bo carried away with the waste water, after it has passed 

 through the machines. 



