We believe that the light alloys of iron and °*
manganese are those which are disintegrated lea^
rapidly, in contact with the air, and even wft* 1
chemical agents.
2. I shall now mention the principal part of tfr e
criticisms of Mr. Haber — that which deals wi^
electrolytic reactions and their continuity, X?y
a rational alimentation of the bath in proportion-
to its decomposition,



APPENDIX. «7

The bath especially experimented with by us,
nd of which the composition is given above,
orresponds to the formtila i2NaCl+Al 2 F 6 ,6NaF.
In proportion to its decomposition by the current,
it is fed by a mixture of alumina and fluoride of
aluminum: nAl 2 3 +Al 2 F6, with this condition, that
A/ 2 3 should be raised in proportion as the tempera-
ture was lowered; this last observation had not
yet been made by me in the accounts of my previous
studies, or at least it had not been presented in that
form.
Experience has shown us that in the passage
of the current events take place as though, of all
the compositions present, only AI2O3 disappeared,
whatever may be the hypothesis formulated as
to the electrolytic reactions properly so-called and
the local reactions; that is to say, the reactions
do not interfere with the counter-electromotive
force.
First Hypothesis. — In case one admits that AI2O3
dissolves in the bath and sinks, and that it is, of
*11 the electrolytes present, the one that is attacked
^y the current — this is the hypothesis put forward
>y Heroult and Hall — the principal electrolytic is
depressed by the relation

Al 2 3 =Al 2 + 3 ,

^hich becomes, when the quantity of current set in
Action equals 96,540 coulombs (chemical equivalent



IlS APPENDIX.
