172 



MR. WILLIAM FAIRBAIRN 6N THE 



50 tons, at the rate of 13'33 miles per hour, a greatly in- 

 ferior duty to that obtained by the leading engine itself on 

 the 28th of February. 



The only reason for this discrepancy would be the im- 

 perfect state of the assistant engine, which, in this and the 

 former Tables, appears to have given out a very small pro- 

 portion of the power, probably little more than sufficient to 

 carry its own vi^eight up the incline. On the other 'hand, 

 the leading engine must have generated steam rapidly, and, 

 as usually happens in surmounting gradients, at a high 

 pressure, which at once accounts for the great difference 

 which exists in the duty performed by the single and double 

 engines respectively. 



TABLE XII. 



PASSENGER TRAINS. 



