472 
Mr Ferraboschi, A double Sulphate of 
Experiment IV. Combustion of the substance. 
This was done in the ordinary way with lead chromate ; 
Weight of substance T4997 g. 
Weight of C0 2 T640g. 
Weight of H 2 0 ‘6322 g. 
Experiments II., III., and IV. were all made with one crystal 
of the substance. 
Calculation of Results. 
Percentages 
Found 
Calculated from formula 
proposed above 
F rom Expt. I. 
Al. 
7-07 
7-00 
„ „ II. 
S. 
16-50 
16-55 
„ „ HI. 
N. 
11-1 
10-9 
„ , iv. 
rc. 
2-98 
3-10 
IH. 
4-73 
4-68 
The following calculation was made as a check upon the 
analysis : — 
Percentage of guanidine, CN 3 H 5 ... 15-39* 
,, ,, A1 2 0 3 ... ... 13-32 (calculated from Expt. I.) 
„ „ S0 3 41-20 ( „ „ Expt. II. ) 
„ H 2 0... ' 30-511 
100-42 
In order to prove that the crystals obtained were of constant 
composition, another sample was examined as in Experiment I. 
Weight of substance ‘4872 g. 
Weight of A1 2 0 3 ‘0646 g. ; 
whence, Percentage of A1 7 -03. 
* Wt. of CN 3 H 5 = (wt. ofC + wt. of N)x^S = (2-98 + 11-1) ^^ = 15-39. 
Ot'Uu 
t H present as H 2 0 = total wt. of H-wt. of H in CN S H 5 = 4-73 - (15-39 - 14-08) 
= 3-42; 
.-. wt. of H 2 0 = 3-42 x SpU 30-51. 
