Page 300

300 Wisconsin Academy of Sciences, Arts, and Letters.
liberated from a magnesiuml chloride solution when the powder
was present in excess, the action being finally checked by the
accumulation of the precipitate, formed; but up, tol the maxi-
mum, the quantity of hydrogen disengaged was nearly propor-
tional to the amount of magnesium added. After magnesium
had acted upon the solutions of the chloride and acetate, these
latter were found to contain but a relatively slight excess of
base. The analytical data. show that the precipitates formed.
were very basic chloride and acetate of magnesium respect-
ively. In the case of the sulphate of muagnesium the solution
was much weaker after the magnesium had acted upon it, a
very considerable portion of the salt having been thrown down
in combination with the hydroxide of magnesiun  in formi of
a basis sulphate of magnesium,. Lemjoine's explanation of the
action. of magnesium on solutions of magnesium salts is that in
these solutions the salts are slightly decomposed into iydroxide
of magnesium and free acid. This acid acts on the metal fornmr
ing hydrogen and a basic salt which breaks up! into the nor-
mial salt and hydroxide of magnesium; the latter finally drovs
out of solution and the reaction begins anew. In, advancing
this explanation it wo-uld certainly seelm that Lemoine did not
give. due. weight, to' the fact that, the reaction of the solutions
of the magnesium salts toward indicators is perfectly neutral
at the outset, and that soon after introducing the magnesium
it becomes alkaline and remains so while the liberation of hy-
drogen continues unabated. There a-re thus no facts upon
which to base the assumption that the salts he used are even
slightly decomposed by water into free acid and magnesium hy-
droxide.
  H. Mouraourl again directed attention to the fact that mlag-
nesiurn liberates hydrogen readily not only from solutions of
it's own salts, but from solutions of other salts as well. He
found solutions of the carbonate, chloride, oxalate and sulphide
of ammonia strongly acted upon; but no action was observed
in the' case of solution of fluoride of ammonium.  S'odiumi car-
bonate, acetate and tetraborate solutions were strongly acted
  iComptes rend. 130, 140, 1900.
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