320 SCIENCE IN SHORT CHAPTERS. 



Then, again, anthracite must not be stirred and poked 

 about; once fairly started it burns steadily and brightly, 

 demanding only a steady feeding. The best of the special 

 grates are more or less automatic in the matter of feeding, 

 and thus the trouble of lighting is fully compensated by 

 the absence of any further trouble. 



As regards the supply. This for London and the greater 

 part of England will doubtless be derived 'from the great 

 coal-field of South Wales. The total quantity of available 

 coal in this region after deducting the waste in getting, 

 was estimated bythe Government Commissioners at 32,456 

 millions of tons. It is very difficult or impossible to cor- 

 rectly estimate the proportion of anthracite in this, but 

 supposing it to be one tenth of true anthracite it gives us 

 3245 millions of tons, or about enough for the domestic 

 supply of the whole country during 100 years, assuming 

 that it shall be used less wastefully than we are now using 

 bituminous coal, which would certainly be the case. But, 

 including the imperfect anthracite, the quantity must be 

 far larger than this, and we have to add the other sources 

 of anthracite. 



We need not, therefore, have any present fear of insuf- 

 ficient supply ; probably before the 100 years are ended we 

 shall find other sources of anthracite, or even have become 

 sufficiently civilized to abolish altogether our present dirty 

 devices, and to adopt rational methods of warming and 

 ventilating our houses. When we do this any sort of coal 

 may be used. 



COUNT RUMFORD'S COOKING-STOVES. 



IN the preceding chapter I described Count Rumford's 

 modification of the English open firegrate which eighty 

 years ago was offered to the British nation without any 

 patent or other restrictions. Its non-adoption I believe to 

 be mainly due to this it was nobody's monopoly, nobody's 

 business to advertise it, and, therefore, nobody took any 



