of ammonia by the reduction of nitric acid. To determine the manganese
in peroxide electrolytically precipitated, it is heated to bright
redness in the platinum capsule until the weight becomes constant. The
results are too high.

_Selenium and Tellurium._--Both these bodies are readily and
completely reduced by the current either in acid or alkaline
solutions. Selenium is thrown down at first of a fine brownish red,
which gradually becomes darker. The deposit of tellurium is of a
bluish black color. If the current is feeble, the deposit of selenium
is moderately compact; that of tellurium is always loose, and it often
floats on the liquid. A strong current precipitates both as powders.
The positive pole is coated during electrolysis with a film of a dark
color in case of selenium, but of a lemon yellow with tellurium. As in
case of arsenic and antimony, the hydrogen evolved at the negative
pole combines with the reduced substances, forming hydrogen, selenide,
or telluride, which remain in part in solution in the liquid. The
reduced metal separates out at the anode in a friable
condition.--_Zeitschrift fur Analytische Chemie, and Chemical News._

* * * * *




THE ELECTRO-CHEMICAL EQUIVALENT OF SILVER.



A very careful and important determination of the electrochemical