128 M. Bo-zelius on the [Aug. 



coloured substance remained, which was thoroughly washed 

 with alcohol. Water extracted the greater portion of this sub- 

 stance : the solution gave with oxalate of ammonia a white pre- 

 cipitate, which was converted by calcination into carbonate of 

 strontitan ; but its quantity was so small that I could not deter- 

 mine its weight, nor indeed could J have satisfied myself com- 

 pletely that it consisted of strontitan, had I not succeeded in 

 obtaining it in larger quantity from a different source. The 

 substance insoluble in water was oxide of manganese, but also 

 in too inconsiderable quantity to admit of being weighed with 

 precision. 



e. The solution precipitated by oxalate of ammonia was 

 evaporated to dryness, and the saline residue decomposed by 

 calcination. A white earth was left, weighing 0-054 gramme. 

 Water dissolved from it 0*005 gramme of an alkaline carbonate, 

 which neither attacked the platinum crucible in a red heat, nor 

 did it yield a difficultly soluble salt with muriate of platinum. 

 It was, therefore, soda; and it appears to have formed, during 

 the evaporation of the water, an insoluble compound with the 

 silica and the magnesia, or lime, which was first decomposed 

 by the nitric acid. 



f. The remaining 0'049 gramme of magnesia was dissolved 

 in nitric acid, and the solution evaporated to dryness. By this 

 means there was separated 0002 gramme of silica, impregnated 

 with a trace of manganese. There remains, therefore, for mag- 

 nesia only 0-048 gramme. 



The following are the results of this analysis : 



Sulphate of soda 16 IS 



Carbonate of soda 0-790 



Chloride of sodium 0-649 



Carbonate of lime ()• 195 



Pure magnesia 0*054 



Peroxide of iron 0-004 



Silica 0-046 



3-356 



The difference between 3-356 and 3-382 arises partly from 

 unavoidable loss, and partly from the magnesia being regarded 

 in the tabular result as completely free from carbonic acid. 



Although the substances which made their appearauce unex- 

 pectedly in this analysis are inconsiderable in quantity when 

 compared with the others, it may nevertheless be worth while to 

 examine each of them more particularly, and, if possible, to 

 determine its amount. 



1. Quantity of the Fluoric and Phosphoric Acids, and the 

 Manner in which they exist in the Water. — In order to ascertain 

 with still greater certainty that fluoric acid constitutes an ingre- 



