The application of scientific truths to the common industries of life is becoming every day more and more a necessity. The village carpenter, no less than the builder of the Niagara Suspension Bridge, makes hourly reference to scientific laws. The carpenter who misapplies his formulae for the strength of materials, builds a house which falls down. The properties of the various mechanical powers are involved in every machine. Every machine, indeed, it has been well said, is a solidified mechanical theorem. The surveyor in determining the limits of one's farm, the architect in planning a house, the builder in planning his estimates, and the several master workmen who do the carpentry, masonry, and finishing, are all dependent upon geometric truths. Bleaching, dyeing, calico-printing, gas-making, soap-making, sugar-refining, the reduction of metals from their ores, with innumerable other productive industries, are dependent upon chemistry. Agriculture, the basis of all the other arts, is in the same condition. Chemical knowledge, indeed, is doing for the productive powers of the soil what the application of steam has done for the increase of mechanical power. The farmer who wishes to double his crops, finds the means of doing so, not in multiplying his acres, but in applying a knowledge of the laws of chemistry to the cultivation of the soil already possessed. Even physiology is adding to the wealth of the farming interest. The truth that the production of animal heat implies waste of substance, and that therefore preventing the loss of heat prevents the need for extra food--which is a purely theoretical conclusion--now guides the fattening of cattle. By keeping cattle warm, fodder is saved. Experiments of physiologists have proved, not only that change of diet is beneficial, but that digestion is facilitated by a mixture of ingredients in each meal. Both these truths are now influencing cattle-feeding. In the keen race of competition, the farmer who has a competent knowledge of the laws of animal and vegetable physiology and of agricultural chemistry, will surely distance the one who gropes along by guess and by tradition. A general diffusion of scientific knowledge saves the community from innumerable wasteful and foolish mistakes. In England, not many years ago, the partners in a large mining company were ruined from not knowing that a certain fossil belonged to the old red sandstone, below which coal is never found. In another enterprise, L20,000 were lost in the prosecution of a scheme for collecting the alcohol that distils from bread in baking, all of which might have been saved, had the parties known that less than one hundredth part by weight of the flour is changed in fermentation.