60 REPORT—1857. 
On the Methods of Analysing the Superphosphates. 
By Professor Vortcker, F.C.S, 
In this paper Dr. Voelcker reviewed the different methods of analysing superphos- 
phate, and directed attention to the fact that the biphosphate of lime in commercial 
superphosphates is decomposed when the latter are boiled out at once with water, in 
consequence of which the amount of soluble phosphate is always obtained too low if 
boiling water is employed for extraction. 
He showed likewise that the amount of organic matter and ammoniacal salts in 
superphosphate cannot be determined as usually done by burning, inasmuch as sul- 
phuric acid is thereby driven out, and the per-centage of organic matter obtained too 
high, 
Sapeihadphates often contain common salt in considerable quantities; in deter- 
mining the alkaline salts, the common salt is obtained as sulphate of soda, and has to 
be stated in the results of chloride of sodium. He next pointed out the variable 
composition of the precipitated phosphates, and recommended in accurate analyses 
the method of Wohler for determining the composition of the phosphates. 
Allusion having been made to the irrational manner of stating the results of analysis, 
Dr. Voelcker described his own plan of analysing superphosphate, of which the fol- 
lowing is a brief abstract. 
Water and nitrogen are determined as usual. 30 to 35 grains of superphosphate 
are exhausted three or four times with two ounces of distilled water each time, and 
then boiled out with sufficient water to obtain an excess of gypsum in solution. The 
insoluble portion is collected in a weighed filter, dried, weighed, and then burned. 
The ash is then dissolved in HCl, the solution precipitated with ammonia, and the 
filtrate from insoluble phosphates with oxalate of ammonia. The portion dissolved 
in water is concentrated with the addition of some HCl to prevent phosphates falling 
down, the soluble phosphates are then thrown down with ammonia, the filtrate from 
phosphates is precipitated with oxalate of ammonia, and the filtrate from lime evapo- 
rated for alkaline salts. In accurate analysis the phosphates have to be analysed. 
On the Proportion of Organic Phosphorus in Legumine. 
By Professor Vortcxer, £.C.S. 
The presence of phosphorus in legumine, contained in it in organic combination 
and not in the form of phosphates, was shown by the author by deflagrating a mixture 
of legumine with carbonate of soda and nitre, dissolving the white residue in dilute 
hydrochloric acid, and precipitating the sulphuric acid with BaCl, removing the ex- 
cess of BnO by pure sulphuric acid, adding to filtrate from BnO, SO% ammonia to 
throw down any phosphates present, evaporating to small bulk, and precipitating finally 
phosphoric acid with ammoniacal sulphate of magnesia. 
In this way the following results were obtained :— 
1. Legumine from green peas, 
Per-centage of sulphur . . . 6 6 ee 6 © + «© + » *870 
F 3 ;ephosphorns!) e/a a es SaaS 
. a MTOR i... TASS Sree ast soto afen o e STEREAS 21g) Sa ee 
2. Legumine from green peas thrown down with very little A, 
Per-centage of sulphur © .° .° .° 1° 2°. 's 2 ee ee oe “ONL 
! Fh suphosphorua,” 25) 6° sates fs es Oe OS 
3. Legumine from green peas precipitated with excess of A. 
Per-centege ofsulphur «we se ee ee ew ew BON 
es - ppepOspHOrus ss ss yet.) e) > ajo) steep 
4, Legumine from while peas. 
Per-centage of phosphorus . . . - » - «© + « « « » 1°92 
bs Se tel ae tree ete el tye. sce 
5. Legumine from white French beans. 
Per-centage of sulphur. 2 1 7 4 + se ew ww ee OD 
nn rp 9) Phosphorus, . 0. isl ws ln es Oe 1:78 
a “ny | 
