PROTECTION OF IRON AND OTHER METAL WORK. 197 
appearance, discolouring all the available objects round 
about. This was strikingly exhibited by the continual 
dropping of the water on an otherwise bright tinned dish 
which had received a coating of red oxide as though it had 
been painted with red oxide paint. On rubbing off, or dis- 
solving off with a little mineral acid, the original clean 
tinned surface was again revealed just as good as new. 
The action may be represented by the following equation : 
2 FeH.(CO;)2 + 30 = Fe.O; + 2 CO. + 2 OH. 
This corrosive action can doubtless be minimised by pro- 
tecting the casing with some vitreous enamel or insoluble 
coating, or by the use of some new form of steel adapted 
for such special purposes, such as a steel containing tung- 
sten, nickel, chrome; or a hard copper-aluminium alloy 
having sufficient resistant properties. But in the bore I 
allude to, the abrading effects of the sand, stones and gravel 
ejected, presents an unusual difficulty; if this could be 
overcome, then a hard resistant casing of some special 
manufacture would probably be the best means to preserve 
the casing from the solvent action of this water. 
