disinfection more than any others. The whole soil of the earth is a great disinfectant, kept in constant activity, being constantly required, holding; in itself the most nauseous and unwholesome things, and still having healthy people living over it. However, the soil may be too full, and at times it becomes so, and therefore we run to places which cannot contain much impurity, such as bare rocks; and in such places we obtain pure air. If in houses we have too much organic matter for the porous substances to oxidize, we must resort to non-porous surfaces; but then they must, like the rocks, be often washed, or excessively exposed to the air or the warm sun.
To purify rooms the air must blow long into them, or every part must have the organic matter rubbed off by the hand. This is a sufficient rule for both hospitals and private houses. Good rubbing will purify furniture, and this our housewives know; long-continued currents of air are also known to be good, but better as a supplement to rubbing. The rules are very easy chemically, but mechanically they are difficult. This is merely a repetition of that which has been said elsewhere, and long ago, although it is here stated in other words. The world must be told every thing in ten thousand different ways before it learns, and it is wearisome to repeat the lesson. I am only saying, also, what every clean house-keeper carries out; and yet there is an apparent novelty in it when we compare it with the sayings and doings of many persons, intelligent and observing although they be.—Air and Rain.
MODERN science, in giving rise to a new order of knowledge, fundamentally contrasted with the older eruditions, among its numerous influences cannot fail to give us a more satisfactory basis for the estimation of mental character and attainment. In proportion as the later knowledge is definite, positive, and universally accepted, does it become a better standard by which the intellectual greatness of men may be judged. In no sphere of mental performance can a man's work be brought to such decisive tests as in science. Each department has its special and authoritative cultivators who subject all new ideas to an inexorable ordeal of verification. While, in the various fields of literature and art, reputations may be made with little regard to substantive merit, because their appeal is to taste and feeling, and the canons of criticism are uncertain, in science, on the other hand, the rules of judgment are unmistakable, and men are measured by the quality and extent of what they have really accomplished. Human nature is, of course, imperfect, and in science, as elsewhere, its imperfections may