330 J. M. Ordway on Nitrates of Iron. 
ferrous nitrate, is to dissolve the protosulphid of iron in nitric 
acid of less sp. gr. than 1:12, no considerable elevation of tem- 
perature being allowed. Though protonitrate crystals are very 
unstable, a moderatel y strong solution may be evaporated with- 
out mneh risk by a heat not exceeding 60°C, As the strength 
increases, however, the temperature must be lowered, especially 
if there is an excess of acid. thus Fs arti with gre eater 
oot 
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29, eee séliition made directly with sulphid of iron and nitric acid 
of sp. gr. 1:08, contained 29'p.c. of FeO, NO,, 6HO, and 0°6 p.c. of free 
acid. Some of it heated slowly remained clear and agva 2 while 
o 83° 
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b.—Some of the sokilton mixed with about its own weight of water, 
continued unaltered till it was heated to 100°C. It required “ five 
minutes boiling to effect a complete rearrangement of its elem 4 
¢.—Some of the solution on being merely mixed with one- Daas of its 
weight of pure nitric acid of sp. gr. 1°42, at once gave off gas and made 
a clear, ay red li 
.—Some of the solution was mixed with nearly its own weight of 
 nitrie acid as sp. gr. 1:10 and heated slowly. At 66°C., it started and 
eel changed to pernitrate. 
mixture of 28¢. of the solution with 11g. of pure nitric acid — 
. 116, began to alter at 77°C. if 
_____ 30.—A solution of the crystals, saturated at 15°C. and containing 7 
p-¢. of FeO, NO,,6HO, was heated in a water-bath. It began to give ? 
off gas at 85°C. At 88° the rearrangement went on violently an 
soon finished. 
~The etystals themselves while still wet, see be kept in the 
cold without alteration; but when they are quite free ar 
_ mother iquor, they are apt to start suddenly. even at the 
mperature of the air, and undergo a rapid iene 
a a dark Hse Aone basic pernitrate being produced. The compo" 
sition the past y mass, in one instance, was found to be aboub 
‘ nano rit was ¥eN,.,.. These products are apparea ny | 
i potubie in w ; bat the liquor i is slightly opaline when look 
“ sci ie i a when seen by transmitted light, The erys 
ives therefore change to a substance almost perfectly 
water, while solutions of the crystals, by spontaneous — 
me rusty, a portion of the peroxyd assuming ee 
state, 
: a i ar show that neutral solutions, ee : 
- n very ng, _ bear a pretty high temperature. Wea® — 
tolations be brought for a moment to the boiling point 
without i iate it Bat ee 
