MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOxMPOSITION. 403 
r0785 grin. left 0‘0245 grm. ash, which after treatment with sulphuric acid, weighed 
0’0455 grill. =4‘21 per cent. 
IV. 0’4990grm., obtained by means of ammonia, gave 0'9780 carbonic acid and 
0’2320 water. 
0'7385 grm. left 0‘0155 grm. ash, which after treatment with sulphuric acid, weighed 
0’0395 grm. =5'34 per cent. 
After making the due corrections for the ash in the way just described, these 
numbers correspond in 100 parts to — 
Carbon . . . 
I. 
. . 56'66 
II. 
56-81 
III. 
5606 
IV. 
56-46 
Hydrogen . . 
. . 6*13 
5-50 
5*54 
5-45 
Oxygen . . . 
. . 37*21 
37*69 
38*40 
38-09 
leading to the formula CjeHgaOag, as the following calculation shows: — 
Carbon 
Eqs. 
... 56 
336 
Calculated. 
56-75 
Hydrogen 
... 32 
32 
5*40 
Oxygen . 
... 28 
224 
37*85 
592 
100-00 
The lead compound was prepared by dissolving the substance in a small quantity 
of water, adding an alcoholic solution of acetate of lead, separating the red precipi- 
tate which was formed, by filtration, adding a little ammonia to the filtered liquid, 
taking care to leave an excess of rubidehydran in solution, filtering the precipitate 
and washing it with alcohol. 
0'.5705 grm. of this precipitate, dried in the water-bath, gave 0‘8110 carbonic acid 
and O’ 1465 water. 
0*3180 grm., treated with sulphuric acid and heated, left 0’2200grm. residue, which 
on being treated with hot water, yielded to the latter O’OMOgrm. sulphate of mag- 
nesia, leaving 0’2060 sulphate of lead. 
These numbers lead to the following composition : — 
Carbon . . . 
Eqs. 
. 56 
336 
Calculated. 
29-20 
Found. 
29-20 
Hydrogen . . 
. 32 
32 
2-78 
2-85 
Oxygen . . . 
. 28 
224 
19-48 
Oxide of lead . 
5 
558-5 
48-54 
47-66 
1150-5 
100-00 
The deficiency in the oxide of lead in this analysis arose without doubt from the 
oxide being in part replaced by magnesia. 
It appears therefore that rubidehydran differs from rubian merely by containing 
the elements of two equivalents of water less, and the origin of the different products 
