After all the chlorine has been passed in, it is necessary to be certain that the mixture is slightly alkaline, since any excess of free chlorine in the solution prevents the formation of hydrazine.
"Organic-Syntheses"
Conant, James Bryant
If the crude hydrazine is brown, it is advisable to use a little bone-black.
"Organic-Syntheses"
Conant, James Bryant
It is possible for one man, simultaneously evaporating six dishes of the hydrazine mixture, to turn out from 20 to 25 runs in nine hours.
"Organic-Syntheses"
Conant, James Bryant