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SCIENCE PROGRESS 



completely filled, the lamps under flasks B and D are also 

 extinguished. When B is quite full, flasks A and B are 

 quickly cooled by surrounding them with cold water. The 

 valve at F is then closed. By this means the bright specimens 

 are immersed in water practically free from air, oxygen or 

 carbonic acid and may be kept under observation for any 

 desired length of time. This experiment has been repeated a 

 great number of times with different samples of iron and steel 

 and no rusting has ever been observed unless air was allowed 

 to enter." 



" It has been shown that the electrolytic theory ot the wet 

 oxidation of iron is based on the premise that iron must first 

 go into solution, an equivalent amount of hydrogen being set 



Fig. I. 



free. The resulting ferrous hydroxide in solution betrays its 

 presence by producing a pink coloration with the phenol- 

 phthalein indicator. In every experiment made the pink colour 

 was seen, although in some cases the colour developed slowly 

 and only after the lapse of a number of hours. That the colour 

 was not due to the action of water on the Jena glass is shown 

 by the fact that no colour appeared on the blank side of the 

 experiments." 



In other words, it is argued by Cushman and Gardner that 

 a certain amount of iron was dissolved and that it was dissolved 

 by the action of water alone. Further proof that iron had been 

 dissolved is given by their statement made with reference to 

 other similar experiments that on allowing oxygen carefully 

 purified from carbonic acid to bubble through the flasks rust 



