"It is true that some processes of manufacture have not been consequences of abstract scientific discovery--that they originally resulted from alterations made in the rudest appliances, and that they have been directed and improved by the results of simple experience. For ages past we derived the benefit of scientific principles without a knowledge of their existence. We trod in the beaten paths of experience ignorant of the truth that we were acting in unison with fixed and certain laws. Numerous arts and processes were in extensive operation long before the principles involved in them were at all understood. The arts of enamelling and of iron smelting were known hundreds of years before we were acquainted with the principles of chemistry. In some rare instances also the recorded results of daily experience in practical matters, tabulated and studied, have ultimately led to the discovery of scientific laws; but all this is merely the making use of our ordinary experience for the advancement of knowledge, instead of making _special experiments_ for the purpose." Many of our processes and manufactures, those of glass and copper for example, are of such great antiquity, it is impossible to ascertain with certainty the special circumstances under which they originated; but after we have fully considered the ways in which {20} various modern trades and manufactures have first arisen, we shall come to the conclusion that all manufactures and improvements in manufacturing processes, must have been first produced by the same general means, viz., new observations, although the special circumstances connected with the origin of each were different. Let us consider German-silver and its manufacture. That substance is an alloy of copper, zinc, and nickel; it owes its peculiar whiteness or "silver-like" appearance to the latter metal, and cannot be made without it; it is certain, therefore, that by whatever means that metal or the alloy was discovered, the discovery was the origin of the German-silver manufacture, and was essential to all manufactures, processes, or appliances in which German-silver, nickel, or any of its compounds are used. Nickel was discovered by Cronstedt during the year 1751, and its compounds were chiefly investigated by English and foreign chemists. Cronstedt found it as a peculiar metal in the mineral called kupfernickel, whilst chemically examining the properties of that substance. The general method by which he discovered it was careful experiment, observation, and study of the properties of matter.