Double sulphate of nickel and ammonium 10 ounces.
Ammonium chloride 4 "
Potassium chloride 2 "
Distilled water 1 gallon.
The salts are dissolved in the water (hot), and the solution is worked
at the ordinary temperature, about 16 degrees C.
The zinc may be cleansed in any suitable manner, but must be perfectly
clean, of course, and finally rinsed in clean cold water and placed in
the bath as quickly as possible; care being taken that it is connected
before it touches the solution.--_Electrical World_.
* * * * *
A catalogue, containing brief notices of many important scientific
papers heretofore published in the SUPPLEMENT, may be had gratis at this
office.
* * * * *