AFF

AF F

C 16 )

11.07; and 15.6, are respectively in the pro-portions of 1, 1| and 2.

The yellow oxyd is the only one which entersinto the salts of lead.

Lead and Sulphur. 100 parts of lead mix-ed with as much pure sulphur, and heated ina close vessel, as long as any sulphur wassublimed, produced 110.6 of the sulphuret; sothat 100 parts of lead when thus united withsulphur absorb 15.6, which is exactly twicethe weight of oxygen united with the samequantity of lead in the yellow oxyd. On thiscoincidence a law of combination is deducedwhich will be presently mentioned.

This sulphuret of lead is therefore thus com-posed :

Lead .Sulphur

100

15.6

86.51

13.49

115.6 100.00

Lead - 86.51Sulphur 13.49

A hundred parts of the sulphuret of lead lastdescribed were digested in nitro-muriatic acidtill the whole was converted into sulphat oflead, the sulphur and lead both acquiring oxygenfrom the nitro-muriatic acid. No productwhatever was yielded from the sulphuret butthe sulphat of lead, which was perfectly neu-tral and weighed 126.5 parts. The respectivechanges that took place therefore, supposingthe base of this salt to be the yellow oxyd, areas follows:

Oxygen.

with 6.748 produce 93.258 oxyd of lead- 19.752 - 33.242 sulphuric acid

Sulphuret of lead 100.00

26.500

126.5 sulphat of lead

Two things are to be particularly noticedhere:

One of them is : that the sulphur of the sul-phuret of lead was exactly sufficient when con-verted to sulphuric acid to saturate the lead ofthe same sulphuret when converted to the sub-oxyd of lead.

The other thing to be noticed is : that thequantity of the sulphur in the sulphuret wasalmost exactly double the quantity of oxygentaken up by the lead of the sulphuret, being as

13.49 to 6.748.

From the former of these facts the authorinfers as a general rule, that a metal combineswith sulphur in such a proportion, that whenthe sulphur is converted to sulphuric acid andthe metal to an oxyd, the sole product will bea neutral sulphated oxyd of the same metal.

From the latter of these two facts the authorinfers: that in every neutral sulphat the oxygenof the base equals half the weight of the sulphurof the acid with which it is saturated.

The composition of sulphuric acid is inferredfrom the above oxydation of sulphuret of lead,to he in the proportion of 13.49 of sulphur to19.752 of oxygen, the whole addition of oxygento the sulphuret being 26.5, and 6.748 of thisbeing estimated as the portion belonging to theoxyd of lead.

Sulphuric acid therefore consists ofSulphur 40.58 — 100.000Oxygen 59.42 — 146.426

According to the second of the two propo-sitions just mentioned, 100 parts of sulphuricacid therefore will saturate so much of anyoxydated base as contains *°^ — = 20.29 ofoxygen.

As an exact determination of the elements ofsulphuric acid is of great importance in ana-lysis, the author proceeds to compare the abovementioned result with those produced by othermodes of operating.

Both Bucholz and Klaproth have sought tofix the elements of this acid by acidifying agiven quantity of sulphur, and then combiningit with the barytes of a known quantity of somesoluble barytic salt. The analysis of sulphatof barytes depends also on that of carbonaf ofbarytes, out of which all the barytic salts areprepared. By multiplied experiments the au-thor fixes the elements of carbonnt of barytesat Carbonic acid 21 6 — J00

Barytes 78.4 — 363

100.0 463

Of this carbonat, 100 parts (containing 78.4of base) gave from 118.6 to 119 parts of sulphatof barytes, which will give for the elements ofsulphat of barytes within of the follow-

ing numbers:

Sulphuric acid 34 — 100

Barytes 66 ’— 194

246.426

100.00

100

294