Prevention of Iron and Steel from rusting. 373 



boy appointed to attend the engine. Impatient to finish his 

 work, he had put a piece of timber between the top of the 

 safety vaU'e and a beam above it, so that it could not rise to 

 allow steam to escape when produced in greater quantity than 

 required. He even went away to fish in the river. In the 

 mean time the engine was stopped by another workman, 

 who knew not what the boy had done, and in a short time 

 the nlischief we have stated followed. The boy had re- 

 turned, and was in the very act of removing the piece of 

 wood he had so imprudently put over the valve when the ex- 

 plosion took place. He was the least hurt of all w ho were 

 near the spot. 



This accident ought to serve as a warning to engineers to 

 construct their safety valves in such a manner that common 

 workmen cannot stop them at their pleasure ; which may be 

 easily done. 



From the way in which part of the boiler was bent, which 

 was constructed of cast iron nearl}' an inch in thickness, it 

 is thouglit the steam must have acquired an expansive force 

 equal to 500 pounds on the square inch before it gave way 

 — a force much beyond any that can ever be required. But 

 though this shows that engines on Mr. Trevethick's plan 

 may, with proper precautions, be worked with as much safety 

 as those on the common principle, such an accident as the 

 one we have stated cannot fail to intimidate some people 

 from adopting them. It is therefore with much pleasure 

 we state that a boiler on a new construction, calculated to 

 bear a much higher degree of expansive force than can ever 

 in any case be required, has bicn lately invented by a very 

 able engineer, Mr. Woolf. It consists of a combination of 

 cylindrical tubes, which unite the double advantage of ex- 

 posing a much larger surface to the action of the fire th.an the 

 common boiler, while they possess a much greater degree of 

 strength. This invention appears to us so important, that 

 we shall take an early opportunity of laving a description of 

 it before the public. 



MKTHOD OF Pr>EVENTI\G IRON AND STEEL FIVOM 

 UUSTING *. 



C. Conte has found out a method of prevenllng the oxi- 

 dation of iron and steel, or, to speak in language more ge- 

 nerally understood, to prevent iron and steel from rusting. 

 'J'liis method consists in mixing with fat oil varnish a half, 

 at least, or rather four-fifths, of well rectified spirit of tur- 



'' From the MiJ^qasr» V.nyclol>idl(iue . 



A a 3 pentino. 



