And for geology, again.  As I do not expect you all, or perhaps any of you, to become such botanists as General Monro, whose recent “Monograph of the Bamboos” is an honour to British botanists, and a proof of the scientific power which is to be found here and there among British officers:  so I do not expect you to become such geologists as Sir Roderick Murchison, or even to add such a grand chapter to the history of extinct animals as Major Cautley did by his discoveries in the Sewalik Hills.  Nevertheless, you can learn—­ and I should earnestly advise you to learn—­geology and mineralogy enough to be of great use to you in your profession, and of use, too, should you relinquish your profession hereafter.  It must be profitable for any man, and specially for you, to know how and where to find good limestone, building stone, road metal; it must be good to be able to distinguish ores and mineral products; it must be good to know—­as a geologist will usually know, even in a country which he sees for the first time—­where water is likely to be found, and at what probable depth; it must be good to know whether the water is fit for drinking or not, whether it is unwholesome or merely muddy; it must be good to know what spots are likely to be healthy, and what unhealthy, for encamping.  The two last questions depend, doubtless, on meteorological as well as geological accidents:  but the answers to them will be most surely found out by the scientific man, because the facts connected with them are, like all other facts, determined by natural laws.  After what one has heard, in past years, of barracks built in spots plainly pestilential; of soldiers encamped in ruined cities, reeking with the dirt and poison of centuries; of—­but it is not my place to find fault; all I will say is, that the wise and humane officer, when once his eyes are opened to the practical value of physical science, will surely try to acquaint himself somewhat with those laws of drainage and of climate, geological, meteorological, chemical, which influence, often with terrible suddenness and fury, the health of whole armies.  He will not find it beyond his province to ascertain the amount and period of rainfalls, the maxima of heat and of cold which his troops may have to endure, and many another point on which their health and efficiency—­nay, their very life may depend, but which are now too exclusively delegated to the doctor, to whose province they do not really belong.  For cure, I take the liberty of believing, is the duty of the medical officer; prevention, that of the military.

Thus much I can say just now—­and there is much more to be said—­on the practical uses of the study of Natural History.  But let me remind you, on the other side, if Natural History will help you, you in return can help her; and would, I doubt not, help her and help scientific men at home, if once you looked fairly and steadily at the immense importance of Natural History—­of the knowledge