92 Mr. George Thomson on Blast Furnaces. 



nace nor to the make. The results given from the Glasgow furnaces 

 are taken from data by M. Dufrenoy in 1833, — but since that period, 

 the areas of nose pipes, and the number, and consequently make, 

 have been increased as at other places. 



This table shows that the quantity of blast varies with different 

 material to produce the same quantity of iron, especially with cold 

 blast, — with hot blast the areas bear little relation to the actual quan- 

 tity of air injected, which cannot be arrived at without the capacity 

 of the blowing cylinder and speed of engines. 



The tables and statements are much more general than I could 

 have wished; at the same time I think they sufficiently show that, 

 1st, there is a remarkable difference in the material of different strata 

 in the same coal fields ; 2d, that modification of shape and alteration 

 of capacity have a very considerable effect ; and 3d, that the effect of 

 blast is very various with different materials ; that an alteration of its 

 temperature, with certain coals, produces a saving of in some cases 

 one-half, in others two-thirds of the quantity, while with other coals 

 the difference is scarcely perceptible, and the quantity of blast has 

 little relation to the quantity or bulk of material acted upon. 



The improvements in iron smelting have been effected simply by 

 the observation and consequent successive trials of practical men; 

 they have been the result of no principle previously established, — no 

 tlieory obtained from the laboratory of the chemist: — and further, I 

 think it cannot be denied that the anomalies apparent under each 

 condition into which I have divided my results, present a problem 

 which, as far as chemical analysis has yet gone, it is difficult to solve. 

 And it must surely be admitted that, had these conditions been pre- 

 viously laid down to any one well acquainted, theoretically or prac- 

 tically, or both, with the manufacture of iron, together with a careful 

 analysis of the material here referred to, he would never have predi- 

 cated such results as have in reality accrued. 



That the want of a guiding principle is greatly felt, and its attain- 

 ment greatly to be desired, needs not to be set forth ; and as there is 

 no effect without a cause, I do not see that the number of apparent 

 contradictions in these ought to make us in the least despair of ulti- 

 mately attaining, by the powerful aid of science, a satisfactory rationale 

 of the whole case. This, however, will never be done by avoiding the 

 question — by taking a partial view of facts. 



Mr. John Alston described Williams' apparatus for consuming 

 smoke, and exhibited a model. 



BELL AND BAIN. FRIHTERS, OLASQOW. 



