460 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



out of blast were furnaces of comparatively small capacity. 

 It was not until near the end of the year that a general de- 

 termination to blow out was reached, and pending the agi- 

 tation of this question the few furnaces that w T ere blown out 

 were offset by others (some of them new) that were blown in. 

 On the 1st of February, 1875, of 701 completed furnaces 

 in the country there were in blast 303 stacks, and out of 

 blast 398. Sixty-two furnaces were blown out in January. 

 Since February 1st the number of furnaces out of blast has 

 been slightly increased. The number of new furnaces com- 

 pleted in 1874 was 38, against 50 in 1873, and 41 in 1872. 

 The Secretary has information that since January 1, 1875, 

 no less than 46 new stacks were in course of construction, 

 while others are projected. The bituminous coal and coke 

 district of Ohio showed the greatest increase of production 

 during 1874, while the Lehigh anthracite district of Penn- 

 sylvania is credited with the greatest decrease. 



IRON PRODUCTION IN FRANCE. 



In 1874 France produced 1,360,000 tons of pig (crude) 

 iron, 760,000 tons of wrought iron, and 155,500 tons of steel. 

 3 A, March 13, 1875, 334. 



UTILIZING FURNACE SLAG. 



Mr. \V. Harold Smith proposes to utilize furnace slag by 

 manufacturing therefrom a cheap and serviceable substitute 

 for bricks and stone for paving and building. In the process 

 invented by him the slag is granulated as it comes from the 

 stack, then mixed with two thirds its weight of cement and 

 subjected to heavy pressure. In this manner he has suc- 

 ceeded in producing smooth, firm, solid blocks that have 

 withstood the severest application of heat and cold. Bul- 

 letin, IX., 189. 



MANGANIFEROUS IRON. 



Iron rich in manganese, or sjriegeleisen, has, according to 

 Troost and Hautefeuille, some striking points of difference 

 from common cast iron. For instance, as the latter flows 

 from the furnace it scatters many brilliant sparks, and in 

 cooling disengages, intermittently, bubbles of gas. Spiegel- 

 eisen, on the other hand, from the moment it issues out of 



