On the other hand, it is quite certain that numerous inventions will enhance and beautify the luxury of an age where rational luxury will reign universally. One source of frequent discomfort to-day is the necessity of living always in rooms of one size. Whether we sit alone, or entertain a number of friends, the same apartment has to serve our needs: consequently we are crowded on one day and chilly on the next. With combustion abolished as a heating device, there will be no objection against light sliding walls--a convenience long since adopted by our allies the Japanese--which would be rather dangerous nowadays and not particularly desirable, at all events in England, where we have no means of warming most rooms except a fire on one side, and no means of cooling them at all except by letting in draughts and noise through the window. No doubt when matches and fireplaces, about equally causative of conflagration, have vanished, and when we have invented methods of warming the air in houses without the horrible drying of it caused by the American pipe-stove system, houses will be much more lightly built: and it is certainly not going to be impossible to use thin, light walls without being able to hear in each room every sound that occurs in the next. Concurrently, we shall be able to change the size of rooms--a convenience greater than might be supposed by those who have not thought about the matter. In summer we shall just as easily cool our houses as we shall heat them in winter. Very few servants will be required (another great comfort); and lighting arrangements will naturally be free from their present inadequacy.