drawbacks were capable of being overcome by a judicious appli- 

 cation of fuel. The action of air in burning carbon was then 

 considered, and the reaction between carl)on and carbonic acid gas 

 with the production of carbonic oxide, was illustrated experi- 

 mentally. The properties of both these gases were next referred 

 to, as was also the action of steam on heated carbon, by which the 

 so-called " water-gas " is formed. 



In all these reactions tlie most important fact for the subject 

 under consideration is the generation of heat, and the way in 

 which heat travels from the sun to the earth gives the clue to the 

 most natural way of warming our rooms. Radiant heat can pass 

 tlirough air without warming it, and consequently we may feel 

 warm in a room where the walls are warm although the air may 

 be cool, and even feel cold in one where the air is warm and the 

 walls are cold, on account of the radiation of warmth from our 

 bodies. The great disadvantage of attempting to warm by hot 

 air is due to the increased power of absorbing moisture which 

 such air possesses. In order to obtain radiant heat in our rooms, 

 it is necessary to establish considerable local heat, and such heat 

 can be generated by the combustion of a non-volatile fuel such as 

 charcoal, anthracite, or coke. Charcoal, as being too expensive 

 in this country, is unsuitable. Anthracite, however, is certainly 

 worth attention ; that it generates heat locally is admitted by 

 engineers, who complain that their bars are burned out without 

 the production of enough steam. Coke is considered inferior to 

 anthracite on account of its containing more ash, but is superior 

 on account of its lower cost, and the fact that economy has already 

 been effected by separating some valuable constituents during its 

 preparation. The disadvantages attending the use of bituminous 

 coal are twofold :— firstly, it contains volatile substances whichabsorb 

 heat when assuming the gaseous state, and carry that heat away 

 from the local centre, and secondly, because these volatile constituents 

 are only partially cons,umed before going into the atmosphere, and 

 therefore contribute to a dirtying of the air we breathe — a fact 

 which is only too apparent in all large cities where coal of this 

 character is employed. With regard to the difficulty of consuming 

 anthracite or coke in houses, this cannot be insurmountable, as the use 

 of antliracite is common in some parts of Wales, and in some cities 

 in the United States. But, unfortunately, in a very large 



