Page:Heroes of the telegraph (IA cu31924031222494).djvu/138

 the pioneer of many similar lines, was one of his very last undertakings.

In the recent development of electric lighting, William Siemens, whose fame had been steadily growing, was a recognised leader, although he himself made no great discoveries therein. As a public man and a manufacturer of great resources his influence in assisting the introduction of the light has been immense. The number of Siemens machines and Siemens electric lamps, together with measuring instruments such as the Siemens electro-dynamometer, which has been supplied to different parts of the world by the firm of which he was the head, is very considerable, and probably exceeds that of any other manufacturer, at least in this country.

Employing a staff of skilful assistants to develop many of his ideas, Dr. Siemens was able to produce a great variety of electrical instruments for measuring and other auxiliary purposes, all of which bear the name of his firm, and have proved exceedingly useful in a practical sense.

Among the most interesting of Siemens's investigations were his experiments on the influence of the electric light in promoting the growth of plants, carried out during the winter of 1880 in the greenhouses of Sherwood. These experiments showed that plants do not require a period of rest, but continue to grow if light and other necessaries are supplied to them. Siemens enhanced the daylight, and, as it were, prolonged it through the night by means of arc lamps, with the result of forcing excellent fruit and flowers to their maturity before the natural time in this climate.

While Siemens was testing the chemical and life-promoting influence of the electric arc light, he was also occupied in trying its temperature and heating power with an 'electric furnace,' consisting of a plumbago