THE RUSTING OF IRON AND STEEL. 
263 
alkaline products of decomposition becomes ferrous oxide; where carbonates are 
present ferrous oxide and carbonate are produced. If the resulting solution of 
these ferrous salts is mixed with hydrated ferric oxide the ferrous oxides become 
ferric; there are other re-actions which take place by modifications of the pro¬ 
cess which also produce the ferric condition. The ferrous solution or effluent 
absorbs the oxygen from the air and thus becomes ferric—in which condition it 
is impossible for putrefaction to take place. 
The ferrous oxide in the green and white condition has the property of com¬ 
bining with dissolved organic matter and precipitating it; to get the various 
results the liquid acted on must be in motion, i.e. running through the electrodes. 
In reference to the ferrous carbonate in solution which Professor Dunstan has 
shown you in aerated water—I took my first patent out in 1887-8, and three 
years ago I took a fresh patent for producing nascent ferrous carbonate electro- 
lytically both for immediate use and for storage. Mr. Moore, F.B.C.S., carried 
out experiments on patients with extraordinary results and I have also done the 
same, finding that one-tenth grain dose of ferrous carbonate is ample. I agree 
with Professor Dunstan that medicos are not enthused with the idea of a new 
chalybeate, but I am pleased to say that I am making arrangements for it to be 
exhaustively tried in two hospitals. 
I have also noticed with regard to the oxidation of wrought iron plates that they 
do not oxidise homogeneously but flake after a time; this is partly due to mag¬ 
netic oxide on the surface, known as Blacksmith’s oxide, and also to molecules 
of carbon on the surface. With common cast-iron run into sand-moulds direct 
from furnace the oxidation is homogeneous. 
1 should like to ask Professor Dunstan whether he has tested the re-action of 
carbonic acid on granulated iron as I should like to know whether it is the white 
ferrous oxide or not, that is produced ? personally I have not tested it. Mr. 
Scudder, (Sir Henry Boscoe’s Assistant) told me of this production of ferrous 
carbonate when granulated iron, or iron filings, were placed in a solution of 
carbonic acid, in the year 1890 when I believe he was experimenting with this 
re-action in connection with investigations on my sewage process at Salford. 
I have seen ferrous oxides produced in the presence of carbonic acid by 
electrolysis which on being tested showed no trace of ferrous carbonate. I beg 
to congratulate Professor Dunstan on his most instructive lecture. 
The Chairman :—I am afraid that like the rest of the officers in the room I feel 
too diffident in the presence of so much talent as we have here to-night to ven¬ 
tilate any ideas of my own ; but I read a statement the other day in a book as 
to the amount of injury done by rust and I do not know whether it is true or 
not; it is that the London and North Western Bailway Company lose eighteen 
tons of metal daily from their rails on their whole system by wear and rust and 
I suppose that the greater part of that is due to rust—that the wear comes from 
rust. 
BEPLY. 
Professor Dunstan ;—I am sorry that Professor McLeod has been obliged to 
go away before I was able to reply to his question. He has known of my 
experiments for some time and therefore is in a good position to discuss certain 
points. 
He began by saying that zinc and water when in contact form hydrogen 
peroxide. That is true, if oxygen is present to a minute extent. There are 
many facts that L could not include in this lecture and other facts have been 
established during my work which I have not mentioned. I may say that it can 
be shown that if you shake zinc and certain other metals with water and oxygen 
you do get evidence in certain cases of the formation of hydrogen peroxide; but 
in most cases there is no hydrogen peroxide to be detected at all, certainly not 
