398 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
Eos. 
Calculated. 
I. 
II. 
Carbon 
. . 52 
312 
49-24 
48*92 
48-34 
Hydrogen 
. . 29 
29 
4-57 
4*76 
4*75 
Oxygen 
. . 27 
216 
34*11 
34*60 
35*24 
Baryta . . 
. . 1 
76-6 
12-08 
11*72 
11*67 
633-6 
100-00 
100*00 
100*00 
A lead compound 
was prepared by adding 
to an 
alcoholic 1 
solution of 
acetic acid and acetate of lead and then a little ammonia, taking care to leave an 
excess of rubianic acid in solution. The red preeipitate was collected on a filter, 
washed with alcohol and then dried, at first in vacuo, and then for several hours in 
the water-bath. Its analysis gave the following results : — 
0-5490 grm. gave 0-6760 carbonic acid and 0-1580 water. 
0-6600 grm. gave 0-3760 sulphate of lead. 
These numbers correspond in 100 parts to — 
Carbon 33*58 
Hydrogen 3-19 
Oxygen 2T32 
Oxide of lead 4T91 
The most probable formula for this compound is 2C52 Hag 025+7Pb0, though the 
numbers found by experiment agree better with the formula 2C52 H27 025+7Pb0, as 
will be seen from the following calculation ; — 
Carbon . . 
Eqs. 
. 104 
624 
Calculated. 
33*22 
Eqs. 
104 
624 
Calculated. 
33*55 
Hydrogen . 
. 56 
56 
2-98 
54 
54 
2*90 
Oxygen . . 
. 52 
416 
22*17 
50 
400 
21*51 
Oxide of lead 
. 7 
781*9 
41*63 
7 
781*9 
42*04 
1877'9 
100-00 
1859*9 
100*00 
Another specimen of the lead salt, prepared by precipitating an alcoholic solution 
of the acid with an alcoholic solution of basic acetate of lead, was found to have a 
composition agreeing tolerably well with the formula C52 H28 026+9Pb0. When this 
precipitate was redissolved in a mixture of alcohol and acetic acid, and a fresh pre- 
cipitate was produced by means of a little ammonia, the latter was found to contain 
acid and oxide of lead in the proportion of 1 equiv. of the former to 6 equivs. of the 
latter. It appears, therefore, that these lead precipitates are by no means uniform in 
com position. 
The silver salt was obtained by dissolving the acid in boiling water, adding a small 
quantity of ammonia and then nitrate of silver, when it fell in the form of a dark 
chocolate-coloured flocculent precipitate, which, when viewed under a lens, was 
sometimes seen to consist of small crystalline needles. The precipitate was collected 
