ccvi GENERAL SUMMARY OF SCIENTIFIC AND 



cones, united at their smaller diameters. The mingled air and va- 

 pors pass through a perforated lire-bed into the fuel which is spread 

 over it to the depth of about three inches. The fuel upon the grate 

 is gently lifted by the blast from over the jierforations, the finer par- 

 ticles floating upon the current until entirely consumed, a large pro- 

 portion of the ash passing off with the draft out of the stack. To 

 insure the rapid and complete combustion of the fuel, and prevent 

 the formation of solid masses of clinkers, it is recommended to stir 

 it repeatedly upon the fire -bed with a rabble -shaped instrument. 

 This stirring process, it is declared, is an important element in the 

 use of the fuel under consideration, inasmuch as it serves to relieve 

 the fire from the finely divided ash, which is thus exposed to, and 

 carried by, the draft over the bridge-wall, or through the flues of the 

 boiler into the stack. Another important element in the system is 

 the perforated fire-bed, the perforations in the plate being from three 

 eighths to three fourths of an inch in diameter, and from two to 

 three inches from centre to centre. Wrought iron is preferred as the 

 material of the fire-bed ; and its peculiar construction reduces the 

 loss of fuel through the grate during the stirring j^rocess to a mini- 

 mum, the average loss being declared to be less than two jjer cent, 

 of other coal put into the furnace. A locomotive engine using coal- 

 dirt exclusively for fuel has for some time been engaged in hauling 

 coal trains over the Philadelphia and Reading Railroad, generating 

 steam freely without the use of any portion of the exhaust steam as 

 a draught-promoting agent, the substitute being a continuous sup- 

 ply of air and vapor, introduced into a closed asli-pit, like that de- 

 scribed above, aided by very small jets of live steam in the chimney 

 for the purpose of facilitating the escape of the products of combus- 

 tion. The results, Mr. Wootten claims, obtained from many boilers 

 now using the apparatus before described, show that the hitherto 

 neglected and apparently valueless material known as coal-dirt can 

 be profitably used for generating steam, and that hereafter it must 

 be regarded as a fuel of great value. 



While but little progress appears to have been made toward the 

 solution of the practical difliculties of mechanical puddling during 

 the past year, we may mention that the experiment of ore reduction 

 in Bessemer practice appears to have been successfully accomplished 

 at the Cruzot Works, under the direction of M. Ruduer. From the 

 results obtained by this metallurgist the following statements and 

 recommendations are announced : The introduction of one half ton 

 of pure ore into a charge of seven tons of iron, toward the end of the 

 blow, gave, in M. Ruduer's experimental trials, an excellent quality 

 of steel, with a clear slag containing scarcely any iron. He suggests 

 as a better method that the iron ore be packed about the sides of the 

 converter as fettling, and the same sintered somewhat together by 

 a small charge of coke before running in the iron. One ton of ore 



