356 REPORT—1846. 
5. Phosphate of magnesia 2°45. 
6. Oxide of manganese 0°80. © 
7. Sesquioxide of iron 0°61. 
8. Potass. Weight of slag 27°52. Chloride of potassium 0°46. 
9. Sulphur. The fusion process was adopted. Weight of slag 22°63. 
Sulphate of baryta 1°54. 
10. Phosphoric acid was sought for by the process previously mentioned, 
but not a trace was detected even after standing a week. 
Analysis tabulated. Oxygen. 
LLIGH Ye ele ras ve tebeeeholohars Sey Oy Mabie eidaloncdeidvssis 20°50 
Alumina atiete VORL pitied 7:06 
Eames F.O042 cn: fon Eee S2BE) scans tie 9°60 
DMienegigie 22... 2 aie ince steele Pao cuenee 135 | 10.05 
Protoxide of manganese... 2°89 ...... 0°64 f 
Protoxide of iron........ 2:02 ...... O46 
bthss 3S ee <4 2.61206) 5. Ueeiws tai OT 
Sulphuret of calcium .... 2°15 
Error of lone oni cs, Sy 1:24 
100°00 
6. Anatysis. By J. P. 
1. Weight of slag employed 19°78 grains, after drying i vacuo over sul- 
phuric acid for twenty-four hours. 
2. Silica 8°32. 
3. Alumina 2°62. 
4. Sulphate of lime 15°9. 
5. Phosphate of magnesia 0°57. 
6. Oxide of manganese 0°48. 
7. Sesquioxide of iron 1°09. 
8. Potass. Weight of slag, after drying im vacuo during twenty-four 
hours over sulphuric acid, 20°44 grains. Chloride of potassium 0°87. 
9. Sulphur. Hydrosulphurie acid was evolved by the action of hydro- 
chloric acid. Weight of slag 20°01 grains. The fusion process was adopted. 
Sulphate of baryta 0°65. 4 
10. Phosphoric acid. The alumina and oxide of iron obtained in the pre- 
ceding analysis were fused for a considerable time with bisulphate of potass. 
The mass was digested with hydrochloric acid; some flocculent matter re- 
mained undissolved. To the solution tartaric acid was added, and after- 
wards chloride of magnesium and excess of ammonia. Two days afterwards 
minute crystalline particles were observed adhering to the glass. On exa- — 
mination with a simple microscope, the well-known star-shaped crystals of 
phosphate of magnesia and ammonia were immediately recognised. The solu- 
tion was allowed to stand several days afterwards. The minute quantity of 
crystals was collected on a filter, and washed with cold ammonia-water, until 
no sensible residue was left by evaporation on a plate of glass. After in- 
cineration the phosphate of magnesia weighed 0°06. The phosphoric acid is 
admitted to exist in combination with the alumina. 
