A F F
A FF
( 20 )
oxydated in the same way, and converted into of only If the quantity of the suboxyd, whereasa sulphat with the peroxyd for its base, it is the supersulphuvet is a sulphuration of twice theobvious that the same relative proportions be- quantity in the subsuiphuret. This compoundtween the sulphat and the sulphuret could not therefore, if it could exist, must be one withbe preserved, as the peroxyd is an oxygenation a double portion of acid as follows;
Oxygen.
Iron . . 100.00 with 42.25 . give 144.25 Peroxyd
Sulphur . 117.50 — 172.06 . — 289.56 Sulphuric acid
Supersulphuret 217.50 214.31 433.81 Supersulphat
The resulting salt in this case therefore mustbe with excess of acid, for 289.56 : 144.25 ::100:49.82 so that 100. of sulphuric acid wouldonly unite with 49.82 of the peroxyd of ironwhich contains only 15.27 of oxygen •, whereasit is found by all the previous experiments that100. of sulphuric acid requires for its saturation
Sulphuric acid 100 containPeroxyd . . 65.5 -
These numbers agree sufficiently well withthe laws of combination all along observed, forthe oxygen of the peroxyd is very nearly halfthe weight of the sulphur in the acid, and 100parts of the acid saturate as much peroxyd ascontains 20.1 of oxygen. Therefore the sul-phuret of iron, which is the base of this sulphat,is one in which the sulphur is to the iron as40.58 : 45.40 and would therefore consist ofIron 100.
Sulphur 89.38
189.38
which is an intermediate degree of sulphurationbetween the two actually ascertained by expe-riment. A sulphuret not far deviating fromthese proportions has been actually producedby Mr. Hatchett by distilling the magneticalpyrites with sulphur in a low red heat, as men-tioned in our original article Iron . 1
A perfect analysis of muriat of silver thatcould be depended on even to a thousandth partis a great desideratum, as it would afford ameans of ascertaining the muriatic acid in allthe other muriats, and also the quantity ofoxygen contained in the base of all these salts,if the hypothesis of equal saturation of acidsby so much of every oxyd as contains a givenportion of oxygen be correct. There is nogreat difficulty in ascertaining the quantity ofmetallic silver in a given portion of the fusedmuriat of silver, but it is not so easy to find the
as much of any oxyd as contains 20.29 of oxy-gen, or thereabouts.
But the actual composition of the sulphatedperoxyd of iron (or red sulphat) is very differ-ent. Berzelius finds it by experiment to con-tain about 100 sulphuric acid to 65.5 peroxyd,which are resolved into the following numbers.
Oxygen.
59.42 with 40.5S Sulphur20.10 — 45.40 Iron
exact proportion of oxygen that unites to themetal and of muriatic acid. It is thus attemptedby Professor Berzelius .
Muriat of Silver . 100 of ignited carbonatof barytes contain by experiment 21.6 of car-bonic acid, and therefore 78.4 of barytes,, whichlast when saturated with muriatic acid gives105.6 of muriat of barytes, which salt thereforecontains 78.4 of barytes, and 27.2 of acid..Hence the elements of muriat of barytes areMuriatic acid 25.75 100.0
Barytes , . 74.25 288.4
100.00 388.4
On the other hand 105.6 of muriat of barytesdecomposed by nitrat of silver produce 145.5-of fused muriat of silver, which last thereforecontains all the acid in 105.6 muriat of barytes,namely, 27.2 parts, and 144.5 : 272 :: 100:18.7.Therefore 100. parts of muriat of silver contain18.7 acid and 81.3 oxyd of silver.
Likewise, 100 parts of silver being dissolved innitric acid, muriatic acid added in excess, andthe whole evaporated and fused gave 132.7 ofmuriat of silver, the metal of which thereforeis 100. parts, or (reduced to the proportion of100 parts of the muriat of silver) this will con-tain 75.358 per c?nt. of silver, and 24.642oxygen and muriatic acid.
But as muriat of silver has already beenshewn to contain 18.7 per cent, of muriaticacid, the difference between 24.614 and 18 7,.or 5.942, is the oxygen,.
4 See ChenvDict. vol. 1,.