Excerpt from Treatise on Applied Analytical Chemistry, Vol. 1: Methods and Standards, for the Chemical Analysis of the Principal, Industrial and Food Products Chemical analysis applied tothe examination of industrial and alimentary products plays an important part in the purchase of raw materials, in the control of manufacturing processes, and in the determination of the value, impurities and adulterations of the finished products. It constitutes, in deed, a branch of chemistry worthy of assiduo us cultivation by the technical chemist who wishes to obtain a rational knowledge of his prime materials and finished products, by the hygienic chemist desirous of detecting any additions to or changes in food substances, by the commercial chemist for the exact characterization and evaluation of commercial products, and, in general, by experts and inspectors appointed to exact contractual conditions in connexion with the purchases and supplies of the State. The methods followed in these industrial and commercial analyses are applications of general, analytical and physical chemistry to special cases in some instances they are less rigorous than, and do not attain the precision of, scientific methods, whereas in others the accuracy is that of the most exact scientific investigations. The choice of the method to be used is of considerable importance in practice, which demands processes giving the greatest exactitude compatible with the end in View at the lowest possible expenditure of time and trouble.