About this period, or perhaps immediately after, progress will have been accelerated to an enormous degree by the invention of some new method of decomposing water. The economical analysis of water into its two component gases, whose chemical affinity and antipodal electrical attractions are already utilised to some extent in such appliances as the oxy-hydrogen blowpipe and electrical storage batteries, is a secret capable of extraordinary beneficences to the new age. By burning hydrogen in oxygen we can already produce the greatest heat practically needed in the arts; the electric furnace only superseding this process because it happens to be more manageable. But when we want oxygen and hydrogen, we do not, in practice, now obtain them from water: we only combine them as water in the act of utilisation. The rational line of progress is obviously to seek means of directly decomposing water. When we can do this compendiously and economically we shall have an inexhaustible supply of energy--for water thus used is not destroyed as water, as coal is destroyed, quâ coal, when we utilise its stored energy. The very act of utilising the gases recombines them: and we can use them thus for the production of almost every kind of energy that man at present needs. We can use them for heat by burning them together. We can use them for light by burning them in the presence of any substance capable of being made incandescent. We shall be able to use them to generate electricity by some sort of contrivance akin to the accumulator of the present day (a highly rudimentary invention); and it would be even now a very simple matter to utilise their explosive recombination for the direct production of power as motion. Utilised apart, the constituent gases of water have many other uses and possible uses. Hydrogen, under suitable treatment, yields the greatest obtainable cold, as oxygen and hydrogen together yield the greatest heat. If our flying-machines need a sort of ballast to reinforce their mechanical lifting apparatus, hydrogen is the best possible assistant. And the probable uses of oxygen are yet more numerous. So long as we still burn anything at all except a mixture of oxygen and hydrogen--and ultimately we shall have nothing else left to burn--oxygen is capable of multiplying the efficiency of all combustion. One of the greatest problems of our own day is the disposal of waste products of all sorts--the sources of inconvenience, disease and dirt. Oxygen, if readily and copiously obtainable, is capable of destroying them all. Indeed, it seems likely that medicine, the least progressive of the sciences to-day, will find in oxygen the great propulsive force of its forward movement. In considerably less than a hundred years hence such makeshifts as drugging, and the fighting of one disease by the instalment in the organism of another, will certainly have gone by the board. Antisepsis and Asepsis (the latter almost infinitely the