50 MODERN SCIENCE READER 



system of anastatic printing, a process by which any old 

 or new printed matter could be reproduced. This was 

 rather a success d'estime than a money-making discovery, 

 although it brought the young inventors into European 

 notoriety. The method consists in applying caustic baryta 

 to a page of printed matter, changing the ink to a non- 

 soluble soap, and then applying sulphuric acid to precipi- 

 tate the stearine. The paper was then pressed into a slab 

 of zinc, making an intaglio from which copies could be 

 easily taken. 



Siemens next perfected a method for greatly increasing 

 the heating power of furnaces by compressed air, the results 

 being of immense practical value to the trade. The very 

 high temperature which he was thus able to gain at a small 

 cost of fuel naturally was applied to the working of steel. 

 His method is called the "open hearth process." In this 

 process the charge consists of pig iron, which is placed on 

 the bottom and around the sides of the furnace. Melting 

 requires four or five hours, then pure ore is charged 

 cold into a bath in quantities of four and five hundred- 

 weight. Violent ebullition ensues, and when this ceases 

 more ore is put in, the object being to keep the boiling 

 uniform. Spiegeleisen or ferro-manganese is added, and 

 the charge is cast. The result is steel. Siemens' first im- 

 provement was a rotating furnace, in which coal and iron 

 are put together, and mixed and heated so thoroughly that 

 the result is all that could be desired. So thorough is the 

 process that the hitherto irreducible iron-sands of New 

 Zealand and Canada can be worked to a great profit. 



Coming into direct competition with the Bessemer prod- 

 uct, the open-hearth steel has held its own, its consumption 

 in the United Kingdom rising from 77,500 tons in 1873 to 

 436,000 in 1882. The Lindore-Siemens Company rolls the 

 armor-plate for the British Admiralty, and the steel has 

 been found to be even better than the Bessemer for general 

 ship-building. In 1883 one fourth of the total tonnage of 

 new ship-building was built of Siemens steel. 



