103 
Assuming' the foregoing explanation to be correct in 
principle, the mode of preventing the furrowing of the plates 
complained of, would consist of adopting a plan of construc- 
tion in boilers which would enable them to piesent a uniform 
resistance to the powerful dynamical force exerted by the 
water on the stoppage of the train, and which would cause 
the sedimentary deposit, instead of being collected in angular 
spaces (o act as a cutting tool, to be diffused over as large a 
surface as possible. 
Mr. Fothekgill believed that the corrosion was owing 
to defective construction of the boilers. The caulking: 
hammer had been applied close to the part corroded. This 
would cause the effects of unequal expansions to be principally 
experienced there. 
Mr. M‘Connel observed that the erosion was not, as 
had been alleged, confined to locomotive boilers. He had 
observed similar phenomena in stationary ones as well. 
Mr. Binney drew attention to the fact, that the corrosion 
W’as at the smoke-box end. He believed that it might be 
owing to a chemical action, similar to that which had been 
noted by Dr. Henry, near the leaky joint of a cast iron steam 
pipe surrounded with charcoal. 
