356 * Miscellanies. 



6. Report on physical optics, by Prof. H. Lloyd, Univ. Dublin. 



7. Report on hydraulics, as a branch of engineering, by George 

 Rennie, F. R. S. &c. 



An account of the transactions of the sections is annexed, under 

 the heads 



Mathe 



Min 



3. Mathematical instrunnents and mechanical arts. 



4. Natural History, Anatomy, and Physiology, including Botany, 



Zoology, and Geology. 



5. Anatomy and Physiology. 



6. Statistics. 



* I 



We have no room for an analysis of the reports, and of the doings 

 of the sections we gave some account in Vol. xxviii. 



Tlie following notice, by Dr. Clark, on account of its practical 

 bearing on our vast manufactures of iron, we copy entire. 



Application of the hot blast to the production of cast iron.— In 

 the Clyde iron works,' near Glasgow, during the first six months 

 of the year 1829, every ton of cast iron required for its production 

 eight tons, one and one fourth hundred weight of splint coal, reduced 

 to' coke, at a loss of fifty five per cent. 



During the first six months of the year 1830, after the application 

 of Mr. Neilson's invention, when the air had been heated to about 

 300^ Fahr., every ton of cast iron required five tons, three and one 

 fourth hundred weight of splint coal, converted into coke. Adding 

 eight hundred weight of coal, consumed in heating the air, the saving 

 effected was two and a half tons of splint coal, on every ton of cast 

 iron produced ; and the same blast was found to be capable of ma- 

 king much more iron, the diminished requisite of air being pretty 

 nearly proportioned to the diminished fuel required. But during 

 the first six months of the year 1833, when the temperature of the 

 blast had been raised to above 600^, and when the process of coak- 

 ing the coal had been discovered to be superfluous, and was accord- 

 ingly omitted, a single ton of cast iron was produced by only two 

 tons, five and one fourth hundred weight of splint coal. Ev^en when 

 we add eij^ht hundred weight of coal to heat the air, the quantity oi 

 splint coal required in 1S33, lo make a ton of cast Iron, was nearly 

 one third of what was used in 1829. The blast aiachlnery continued 

 the same, but the same blast made twice as much iron as in 1829. 

 The same coal produced thrice as much cast iron ; the same blast 

 twice as much. 



