314 PROCEEDINGS OF SECTION B. 



From the quotations which follow, it will be seen that the 

 views of the older chemists more closely correspond with my 

 results than those of some of the more recent writers. 



Most modern writers state that rust is non -magnetic, and 

 is formed only in the presence of air, moisture, and carbon 

 dioxide, as follows : — 



(a) Fe + CO^ + O = Fe CO, 



(b) 2FeC03 + = Fe^Og'V 200^ 



(c) Fe^Oy % SH^O = FegOg SHgO = rust. 



This of course may more or less explain the reactions, but 

 it evidently is too neat and complete, inasmuch as it does not 

 account for the large proportion of magnetic oxide which 

 always appears to be present in ordinary rust. 



Another reaction commonly given is Fe + B^O + CO^ 

 = FeCO, + H^, and that the FeCO.^ formed takes up 

 more CO^ and is converted into the soluble acid carbonate, 

 which in turn is converted into the insoluble ferric hydrate 

 (Fe.^O,, SHgO) or rust, and that the CO^ is free to act 

 again, but this is equally imperfect. Mendeleef (" Principles 

 of Chemistry," London, 1891, p. 321), amongst modern 

 wTiters, recognises the fact that rust contains both ferrous 

 and ferric oxides, but makes no mention of its magnetic 

 properties. 



In looking up the matter reference was first made to the 

 later publications, but it was only in those pubHshed over 30 

 years ago that anything was met with really bearing upon 

 the subject, the most interesting and valuable being the Note 

 by Mr. Robbins in the Chemical News for 1859, and the 

 paper by M. Sarzeau in 1860, also in the Chemical News; 

 l3oth of these, however, seemed to have been ignored or 

 overlooked by late writers. 



The following quotations are arranged according to their 

 dates of pubhcation : — 



It is stated in the " Dictionary of Chemistry and 

 Mineralogy," by A. & C. R. Aiken, 1807, on p. 612, that 

 " The common rust which collects upon hammered iron by 

 exposure to air and moisture, and which in time corrodes 

 the thickest bars, is not the simple oxyd, but a carbonated 

 oxyd, or a compound of iron, oxygen, carbonic acid, and 

 water, and is not of itself magnetic, unless mixed with 

 fragments of iron detached by the rusting." 



It is stated, too, that iron will oxidise and hydrogen be given 



