Scientific Intelligence. — Arts. 205 



36. Improvement in the Smelting of Iron. — Heated air for 

 blast furnaces has been used for some time at the Clyde Iron- 

 Works, and with great success. Experiments have proved that 

 iron is smelted by heated air, with three-fourths of the quantity 

 of coals required, when cold air, that is, air not artificially 

 heated, is employed for that purpose, while the produce of the 

 furnace in iron, is at the same time, greatly increased. All the 

 furnaces at Clyde Iron- Works are now blown with it. At these 

 works the air, before it is thrown into the blast-furnaces, is 

 heated 220° of Fahr. in cast-iron vessels placed on furnaces, si- 

 milar to those of steam-engine boilers. It is expected that a 

 higher temperature than 220° will be productive of a propor- 

 tionally increased effect. But this is the subject of experiment. 

 It is supposed that this improvement will accomplish a saving 

 in the cost of the iron m Great Britain, to the amount of at 

 least L. 200,000 a-year. 



37. Artificial Ultramarine. — In preparing this pigment, we 

 must be careful that the mass of silicated natron and alumina is 

 as moist as possible. If il is too much dried before the addi- 

 tion of the sulphur, we will wait in vain for the appearance of 

 the blue colour ; even a greenish-blue tint will not shew itself. 

 But one and the same mass affords different kinds of ultrama- 

 rine, which must be separated from each other by repeated 

 washing. Gmelin remarks, that the success of the operation 

 appears to depend on the co-operation of the air. — Hervistadt. 



List of Patents granted in England from lid July to 15th Sep- 

 tember 1829- 



1829, 

 July 8. To E. Galloway, Southwark, for " improvements in steam-en- 

 gines and machinery for propelling vessels." 

 To J. I'EiiKiNS, London, engineer, for " improvements in ma- 

 chinery for propelling steam-vessels." 

 To T. Kelby, Wakefield, York, and H. F. Baco>j, Leeds, " for 

 their new or improved gas-lamp burner." 

 4. To 11. Crabtree, Halesworth, Suffolk, " for his machine or appara- 

 tus for propelling carriages, vessels, and locomotive bodies." 



