F. H. Storer—Ferment-theory of Nitrification. 445 
chemicals, and the absence of nitrates and nitrites was proved 
by testing each of the solutions and mixtures with iodo-stareh, 
at the beginning of the experiment. 
The bottles were about half filled with liquid, i. e., each of 
them contained about 250 ce. of the solution or mixture allot- 
ted to it. 
The “leached peat” was prepared from some bog-meadow 
mud from the Bussey farm, which had been kept in barrels in 
a dry store-room for three or four years. This thoroughly air- 
dried substance was percolated with pure water until the fil- 
trate gave no reaction for nitrites or nitrates. 
ic and ferrous hydrates were used in the recentl 
precipitated condition; they were made from the correspond- 
ing chlorides by precipitating with ammonia-water, in the cold. 
e bottles were connected with one another, in the order 
indicated, with short pieces of caoutchouc tubing in such man- 
ner that by aspirating at No. 1 air could be made to bubble 
through the water in each member of the series. The corks of 
the bottles and the caoutchoue connectors were covered with 
ilar bulbs hited with potash-lye to remove nitrates and 
nitrites; through a dry bottle, to catch liquid drawn forward 
from the potash bulbs; and through a large drying tube 
charged for two-thirds its length with calcium chloride and one- 
third with soda-lime. 
and 10 namely gave immediate and strong reactions for the 
nitrogen oxides, while the contents of Nos. 1, 2, 3. 4, 5, 6, and 
1 gave no reaction whatsoever. No. 7 gave a reaction, but 
not a very strong one. The reaction seemed to be strongest In 
Am. Jour. Sci.—TsimD — Vou. XV, No. 90,—Junz, 1878. 
