318 SCIENCE IN SHORT CHAPTERS. 



flings the most heat up the chimney, and the least into the 

 room, and, as though we were all struggling to destroy as 

 speedily as possible the supposed physical basis of our pros- 

 perity, we select that coal which in our particular fire-places 

 burns the most wastefully. If we had closed iron stoves 

 with long stove-pipes in the room, giving to the air the 

 heat they had obtained by the convective action of the flame 

 and smoke, there might be some reason for using the flam- 

 ing coal, as the flame would thereby do useful work, but, 

 as it is, we stubbornly persist in using only the radiated 

 heat, and at the same time select just the coal which sup- 

 plies the smallest quantity of what we require. 



No scientific dissertation is necessary to prove the supe- 

 rior radiating power of an anthracite fire to anybody who 

 has ever stood in the front of one. This is most strik- 

 ingly demonstrated by those grates that stand well for- 

 ward, and are kept automatically filled with the radiant- 

 carbon. 



Let us now see why anthracite is a better radiator than 

 bituminous coal. This is due to its chemical composition. 

 Of all the substances that we have upon the earth carbon 

 in its ordinary black form is the best radiator. Anthracite 

 contains from 90 to 94 per cent of pure carbon, bituminous 

 coal from 70 to 85, and much of this being combined with 

 hydrogen burns away as flame. On a rough average we 

 may say that the fixed or solid carbon capable of burning 

 with a smokeless flameless glow, amounts to 65 per cent in 

 ordinary British bituminous coal, against an average of 92 

 per cent in British anthracite. The advantages of anthra- 

 cite as a fuel for open radiating grates are nearly in the 

 proportion of these figures. Besides this it contains about 

 half the quantity of ash. Thus we see that from a purely 

 selfish point of view, and quite irrespective of our duty to 

 our fellow-citizens as regards polluting the atmosphere, 

 anthracite is preferable to ordinary coal on economical 

 grounds, supposing we can obtain it at the same price as 

 bituminous coal, which is now the case. 



Another great advantage of anthracite is its cleanliness, 

 It may be picked up in the fingers without soiling them, 

 and it is similarly cleanly throughout the house. It pro- 



