Page:Heroes of the telegraph (IA cu31924031222494).djvu/125



'Another early subject of mine, the anastatic printing process, found favour with Faraday, "the great and the good," who made it the subject of a Friday evening lecture at the Royal Institution. These two circumstances, combined, obtained for me an entry into scientific circles, and helped to sustain me in difficulty, until, by dint of a certain determination to win, I was able to advance step by step up to this place of honour, situated within a gunshot of the scene of my earliest success in life, but separated from it by the time of a generation. But notwithstanding the lapse of time, my heart still beats quick each time I come back to the scene of this, the determining incident of my life.'

The 'anastatic' process, described by Faraday in 1845, and partly due to Werner Siemens, was a method of reproducing printed matter by transferring the print from paper to plates of zinc. Caustic baryta was applied to the printed sheet to convert the resinous ingredients of the ink into an insoluble soap, the stearine being precipitated with sulphuric acid. The letters were then transferred to the zinc by pressure, so as to be printed from. The process, though ingenious and of much interest at the time, has long ago been superseded by photographic methods.

Even at this time Siemens had several irons in the fire. Besides the printing process and the chronometric governor, which operated by the differential movement between the engine and a chronometer, he was occupied with some minor improvements at Hoyle's Calico Printing Works. He also engaged in railway works from time to time; and in 1846 he brought out a double cylinder air-pump, in which the two cylinders are so combined, that the compressing side of the first and larger cylinder communicated with the suction side of the second and smaller