The influence of evaporation, on hardiness has often been shown in the Gardeners' Monthly. Frost kills trees which are usually hardy, mainly by its influence on drying the tissue, and not on actual cell rupture, as in the the case of plants which we know to be really killed by frost. It is well known that plants will endure a much lower temperature in moist atmospheres than in very dry ones. In the very dry atmosphere of Greely, Colorado, though the temperature does not descend nearly as low as much further north, the hardy apples of other places are often killed. Last winter such very hardy kinds as Tetofsky, Red Astrachan, Fameuse, Duchess of Oldenburg, and Ben Davis, were mostly killed. It is to the merit of the Wealthy, that it has been found to resist the drying winters of Greely better than any other kind.