other proofs of the incorrectness of their conclusions, it may be shown that many valuable practical results have either originated with or were improved by theorists, by those who have experimented with a view to establishing, maintaining, or refuting. Now in regard to agriculture, it may be observed that it had already made considerable advancement when it began to assume a scientific form; but from that period to the present, by deriving assistance from other sciences, and particularly from chemistry, its progress toward perfection has been constant and rapid."
Prof Booth's attention was drawn to the subject of refining cobalt, concerning which little or nothing was known outside of the commercial refineries, by the ill-success of an experiment in mining the metal which was begun in 1845. It was at the Mine La Mott, in Missouri, where he mined a large amount of cobalt, which was sent to England. It was returned as impure; whereupon Prof. Booth at once set to work to discover the best method of refining the metal—and succeeded.
Of Prof Booth's qualities as an instructor Dr. Alexander Mucklé, a pupil of his, as also of Wöhler and Bunsen, and afterward his assistant at the Mint, is quoted as saying: "With this experience of teachers and means of comparison, I can say that Mr Booth had few if any superiors as a teacher of practical chemistry; that he kept abreast of the times by constantly securing the best and latest scientific books and periodicals. A high value was placed upon a course in his laboratory, which soon became widely known and in great repute as a place for learning chemistry; and his teachings are believed to have had a potent influence in developing and disseminating the knowledge of the science and its practical applications."
Prof. Booth was appointed Melter and Refiner of the Mint by President Taylor in 1849, and entered that service on December 10th of that year. The time corresponded closely with the discovery of gold in California. The influx of gold from that source, already heavy, increased rapidly, and added greatly to the work of his office, while the quality of the metal increased considerably the difficulty of dealing with it. The new gold was alloyed with silver in excess of the amount admissible in the coinage, and this had to be extracted. The provisions of the Mint, which had been adapted for the treatment of the bullion which had been previously sent there, were not suitable to the refinement of this gold. New methods had to be adopted, and the whole plan of the parting apparatus had to be reconstructed. It was Prof. Booth's duty to make this adjustment. The process already known in the laboratories had to be expanded and used on a manufacturing scale. "To this work, as well as to all the other labors of his department," says Mr. Robert Patterson, Mr. Booth "brought the full knowledge of
