REPORT OF CHEMIST. 1091 
hydrate was then dried and ignited ; it still contained soda, but was free, 
or nearly so, from sulphur. 
The sodic carbonate and magnesic oxide mixture was, however, 
treated like the other mixture, and its correction in all cases determined, - 
but it usually amounted to but a few hundredths per cent., owing to the 
smaller relative amount of the reagents used. 
The analysis of the ashes was made in the same way as iron ore 
analysis; the ashes were prepared for analysis by burning about 100 
grammes of the coal carefully in a platinum dish or large crucible, 
either over a Bunsen burner, or in the muffle of a cupel furnace. 
TRON OREs. 
The quantity taken for complete analysis was 5 crammes, which 
was treated with hydrochloric acid, evaporated to complete dryness, 
then treated with more acid and water; the residue insoluble in acids 
was fused with sodic carbonate in a platinum crucible, dissolved in 
water and hydrochloric acid, then evaporated dry, and the silica thus 
separated was weighed. The solution was added to that from the orig- 
inal treatment of the ore, and the combined solutions were diluted to 
500 cubic centimeters and aliquot parts used for different determina- 
tions, iron being determined volumetrically in two portions of 50 c¢.c., 
representing 3 gramme each. 
A solution of potassium bichromate was used for titriring the iron. 
The iron being reduced by sodic sulphite (Gf the solution be partly 
neutralized with sodic carbonate, so as to prevent any great excess of 
free acid being present, the reduction is almost immediate) is strongly 
acidified and boiled to expel the excess of sulphurous acid. The rule 
in the laboratory was to boil till the odor of sulphurous acid has ceased, 
and then to continue boiling for five minutes longer. Duplicates by 
this method agree almost exactly. The bichromate method (Dr. 
Penny’s) was employed because of the ease of preparation of the iron 
‘solution and the stability of the standard. 
Phosphorus was determined in 200c. c. of the solution (corre- 
sponding to 2 grammes of the ore). The oxide of iron and phosphoric 
acid being precipitated by, amimonia, washed by decantation, dissolved 
in nitric acid, partly neutralized with ammonia, and the solution pre- 
cipitated by a large excess of “‘ammonic molybdate solution,” the 
precipitate was then washed with the diluted precipitant, dissolved in 
