Margraaf, Fourcroy, Vauquelin, and Dr. Slare also extended our knowledge of the substance; Gahn, in 1769, made the important discovery of phosphorus in bones, and Scheele immediately devised the process now in use by our manufacturers for extracting it from that substance. The commencement of the use of phosphorus for the purpose of getting a light occurred about the year 1803, but it was not until the year 1833 that the invention of phosphorus matches became commercially successful. The use of such matches is now universal, and it has {12} been estimated that the daily consumption of them in Great Britain alone amounts to two hundred and fifty millions, or more than eight matches per day for each individual in the kingdom. "There is nothing on the Earth so small that it may not produce great things." The most abstract and apparently trivial experiments in original research have in some cases led to inventions and results of national and even world-wide importance. The contractions of a frog's leg in the experiments of Galvani, and the movements of a magnetic needle in those of Oersted, have already led to the expenditure of hundreds of millions of pounds in laying telegraph wires all over the earth, and to an immense extension of international intercourse. But the original experiment of Oersted was not discovered without labour, it was only arrived at after many years of research. The saying that "all great things have had small beginnings," is true, not only of electric telegraphs, but also of the great trade of electro-plating, and of the magneto-electric machine which is now largely used instead of the voltaic battery. After Volta had made his small and apparently unimportant experiments on the electricity produced by metals and liquids, various persons tried the effect of that electricity upon metallic solutions. Brugnatelli, in 1805, found that two silver medals became gilded in a solution of gold by passing the electricity through them. Mr. Henry Bessemer, in 1834, coated various {13} lead ornaments with copper by using a solution of copper in a similar manner. And in 1836 Mr. De la Rue found that copies might be taken in copper of engraved copper-plates by the electro-depositing process. Faraday discovered magneto-electricity in the year 1831, by rotating a disc of copper between the poles of a magnet, and he has stated that the first successful result he obtained was so small that he could hardly detect it. This simple experiment was the origin of the magneto-electric machine, and many of these machines are now used for producing the electric light, and for depositing nickel, copper, silver, and gold, instead of by the voltaic battery. These, and other engines, thermic, magnetic, electric, &c, will probably, ere long, be constructed on as large a scale, and as many in number, as the present steam engine.