caused by the vast atmospheric disturbances created by days and weeks of cannonading: and of course it is an old theory that heavy gun-fire "brings down the rain." Military historians say that the number of wet-day battles altogether exceeds any expectation which could have been formed without allowing for effects of this sort. When science has pondered upon the subject, and instituted in an ordered manner experiments of a kind hitherto never taken very seriously, it may very well be that some means less violent than the detonation of explosives may be discovered by the practical meteorologist for creating disturbances in the atmosphere; and while it may not be possible to prevent excessive rainfall at inconvenient times, it seems easy to conceive that when there is moisture in the atmosphere we may be able to bring it down as rain. Of course this is a very different thing from breaking up droughts: and artificial rain-making cannot in itself be anything but a momentary expedient. The effects of deforestation have for some time been observed and the plan of improving waterless areas by the contrary process is already discussed. While it seems rather a "large order" to undertake to meddle with the balance of atmospheric composition on a large scale, especially as we know so little of the conditions that even success might very possibly be attended by unforeseen and perhaps calamitous results, there is nothing intrinsically absurd in the notion that we might adopt means on a vast scale for increasing oceanic evaporation and, utilising the exact foreknowledge of winds and air currents which we shall certainly have achieved, bring moisture and rain to arid tracts or countries suffering from drought. The operation would no doubt require to be stupendous, but the next century is not going to be afraid of stupendous operations; and anticipating vast and unforeseen progress in meteorology, it would be hazardous to believe that no practical use will be made of such progress.