Salt is therefore not avoided, almost as a rule, either by animals or birds; and in those districts where salt lakes are situated (to which interesting fact I have already alluded) are to be invariably seen, not only great numbers of animals, but large flocks of birds of different kinds, showing conclusively that they possess an instinctive preference for those localities where the atmosphere is more or less filled with saline matter, than for those places where it is entirely absent. It is but seldom that animals frequent those spots which are injurious to them; they take good care to avoid them, if possible, and if they detect anything deleterious, whether it be in the air, soil, or water, they migrate to more genial quarters; instinct indicates this necessity, and they accordingly act upon it. It is strange that mere animal instinct should be superior to human reason, and that animal sagacity should be more far-seeing than human forethought! Nothing is more strongly confirmative of this anomaly, if I may call it so, than the partiality which animals entertain for those districts which abound with salt lakes, and the antipathy, or utter indifference, with which some people regard that substance which keeps the body pure, healthy, and, I may say, clean, and which plays such a highly-important part in the animal economy. In the vegetable kingdom salt is by no means an inconsiderable item, and as an agricultural agent it is most invaluable, though its operation therein varies in a remarkable degree; in small quantities it is injurious only to a few plants, while to some it appears to be beneficial in every way. In moderation it is an excellent manure, especially if the soil is of a sandy nature; but in large quantities it is decidedly pernicious to all plants, without an exception, though unequally so. According to experiments made by Dr. Balfour and other eminent botanists, it appears that a solution of the chloride of sodium does not act so deleteriously as solutions of other inorganic substances, and the same effect is observable with a solution of the phosphate of soda: the strength of these solutions, we are told, varied from half a grain to five grains to the ounce of water; the sodium combined with the chlorine forming the chloride of sodium, and with the oxygen forming soda; the potassium, combined with the chlorine, forming the chloride of potassium, and with the oxygen forming potassa. The combinations take place, according to Johnston, in the living plants owing to the natural affinities of these inorganic substances.