312 
ON LIQUOR FERRI NITRATIS. 
acid and heated "with an excess of potash, by •which the iron as 
sesqui oxide, was precipitated. The liquid left afforded no pre- 
cipitate of alumina with an excess of acetic acid. 
The insoluble portion of ashes consists chiefly of carbonate 
and phosphate of lime, phosphate of iron, and silica, without 
magnesia or alumina. 
ON LIQUOR FERRI NITRATIS U. S. P., 1850; AND ON A FORMULA 
FOR SYRUP OF PROTO-NITRATE OF IRON. 
By William Procter, Jr. 
The instability of the so called iC solution of sesqui-nitrate of 
iron " is proverbial, and several attempts have been made to 
render it sufficiently permanent, to be at all times relied 
on. The formula of the Dublin Pharmacopoeia of 1850, which 
is virtually that of Mr, Kerr of Scotland, has been adopted in the 
.United States Pharmacopoeia, with a slight alteration, render- 
ed necessary by the different value of the weights and measures of 
the two codes. The manipulation is the same, viz., to dilute the 
acid with about five times its bulk of water, and add it to the iron 
at once, leaving them in contact until the reaction ceases, w T hich 
is usually stated at twelve hours. The solution thus prepared, has, 
after filtration and dilution, a dark reddish brown color, and is pre- 
cipitated black by ammonia, which indicates clearly that the iron 
is not entirely sesqui-oxidized, and that the solution is a mixture 
of the proto and sesqui-nitrates of iron. 
When this solution is suffered to stand, either in close or open 
vessels, it gradually becomes opaque, and deposits an ochreous 
sediment, which ceases after a length of time, whilst the liquid 
has acquired a much lighter color, is transparent, and is precipita- 
ted in brownish red flocks by ammonia, without any admixture of 
black. The ochreous precipitate is probably a basic, or sub ses- 
qui-nitrate, several of which are known to exist, and one of which, 
according to Grouville (Gmelin's Hand b ; vol. v., p. 269,) has 
the formula 4 Fe 2 3 , N0 5 + 2HO. The proportion of this sub- 
salt that will precipitate from the officinal solution, depends 
