The next and really the most important question--for man should not work for the present and immediate future without the keenest regard to the rights of posterity--is whether, under Dakotan conditions, artesian irrigation is safe; whether there is not danger of its poisoning the ground. Professor Upham unhesitatingly declares that on account of the alkaline and saline properties in these artesian waters a continued use of them for many years would render the land worthless. The assertion is a rounder one than scientific men generally make, and must be received with caution, though emanating from so high a source, for many samples of South Dakotan waters, tested at Brookings, have shown no alkaline reaction at all, and the professor's reasoning seems to rest chiefly upon the North Dakotan waters, which for some reason show larger saline percentages than the South. Then, too, he proceeds on the theory that a yearly supply of one foot of water is necessary, whereas half that amount during the dryest year, supplied through the five growing months, would insure good crops. Four inches last July would have saved the harvest. But anyway the entire amount of saline matter in South Dakotan waters, according to Prof. Lewis McLouth, does not, on the average, exceed one fifth of one per cent. after substracting all inert substances, such as sand, clay, limestone, and iron ores; so that, if six inches of water were applied to the lands, and all evaporated on the surface, the salty crust would be one 1/160 of an inch thick. But as a part of the water would run off into the streams, and much of it, diluted with rain-water, would soak into the ground, the salty ingredients would be mixed at once with at least a foot of the surface earth, and would form less than one fifteenth of one per cent. of the weight of that soil. These ingredients are salts of lime, magnesia, potash, and soda. Now Dr. Bruckner, in an analysis of some soil in Holland, which he pronounces remarkably rich, says that it contains over fifteen per cent. of these same ingredients, or two hundred and twenty-five times as much as six inches of artesian water would give to a foot of Dakotan soil within a year. So it would take two hundred and twenty-five years for this soil to acquire as much of these saline ingredients as the rich soil of Holland already possesses. We might go further into this subject and show that every ingredient of these artesian well salts is a necessary food for many plant tissues; but even if the accumulation of salty substances were thought dangerous, it is to be remembered that during five of the ten years since the settlement of the Jim Valley, the rainfall has been ample, and if this average should continue, the land could be allowed to rest from irrigation for one half of the time so that the floods of rain-water would wash away the surplus saline matter.