188 F. H. Storer—Scheenbein’s Test for Nitrates, 
ulated water that had been boiled five minutes upon a mixture 
of pieces of tin and platinum, nor was any reaction obtained 
from an acidulated solution of nitrate of potash that had been 
similarly boiled. 
Numerous trials were made to discover, if possible, some re- 
ducing agent which, though proper to change nitrates to nitrites 
if not all, of these substances readily form peroxide of hydrogen 
when left in contact with water and air. Among metals,* I 
used as substitutes for cadmium or zine, in testing for nitrates 
by the old method. Both these metals readily reduce nitrates 
to nitrites in dilute neutral solutions at the boiling temperature; 
ut they, as well as magnesium, aluminum, and copper,t cause 
the formation of peroxide of hydrogen also, when boiled m 
another flask 50 c. c. of pure water, plus 00005 grm. N,05, : 
_ the form of nitrate of potash, were boiled upon an equal amout 
as yet, made 10 experiments with the alkali metals or their “at nes ‘ 
Kraut’s Handbuch, i 
* T have, 
+ And various other 
p. 56 
Since the above statement, that iron forms peroxide of hydrogen on ome ca 
ack wit ok ict with Schoe oe eal 
' 
| 
§ 
é 
3 
3 
that the 
well to give the evidence on which it nds. 
pe Bi 
wire for five minutes: the cold liquid was mixed with iodo-zine-s are 
dilute sulphuric acid, and left to stand over night. A purplish gee 
Was obtained. On d, th : ‘ preci sely * reaction. ob- 
- e experiment, similar sad fee 
Served. This coloration is rather less, it should be said, than that one and 
rong ‘ : , and 
the other 
ry In he ano where ret 
‘Sheet j ~1 0 reaction for peroxide of hydrogen was obtain 
* toaty: tint, and no blue coloration could be perceived. 
