326 J. M. Ordway on Nitrates of Iron. 
—and, as will be shown presently, is produced only under cir- — 
cumstances of peculiar constraint. The more commonly occur- 
ring salt, which forms when there is no deficiency of water, is 
the obliqu e rhombic sexhydrate,—Fe,O, 3NO, 1c 
scribed in this Journal in 1850." At that time I was not aw 
that any previous analysis had been recorded; but in 1 little 
work published in 1834, entitled “Manuel du Fabricant d’Indi- 
ennes, par L. J. 8. Thillaye,” is to be found the following pass- 
ave :-—"Si Ton veut obtenir des cristaux de ernitrate, on. fait 
dissoudre lentement le fer dans l’acide nitrique 4 34°, en plagent 
le vase dans un lieu frais. Lorsque la dissolution est a a pew 
prés complete, il se forme des cristaux qui affectent la forme de 
prismes droites a 8 quatre pane et d bases carrées, quelquefois ils 
ont six pans. Le pernitrate cristallise est formé 
with, or have used V lin’s eyes agg of their own. 
observation which Citizen Vauquelin has communicated ” 
us given in Fourcroy’s Chemistry :—“Concentrated nitric acid, 
ashes on an oxide of iron arising from the decom arig of 
t, had been left in contact with it several months. 
eS 
As Vauque lin used concentrated aci 
_had the cubic crystals; but the cubic shiaie ts hot offen = : 
- fied, and the last clause, respecting termination “by a bevel, 
— 8U  & query whether the dimetric form was not ; predicated 
ee a hasty glance rather than from measurement or from care- 
fal foun 
first Baie | se Pee and I may, ‘per rhaps 
to have eis: the first to determine its true ¢ 
: , editor of the Chemical Gazette,—xii, 211,—speaking of Hausmann’s nie 
es sia ine Ty gave the formula Fes Oy 3N0, ieee for it.” He should 
Stl te adan of the still undiseo vered eubie salt, but de- 
the inclination of ehag? es differed 11° from 
