the Water of the Thermal Spring of Bath. 63 



C. Estimation of the total amount of magnesia for con- 

 trol :— 



The liquid filtered off from the precipitate of oxalate cf 

 lime was concentrated, ammonia and phosphate of soda added. 



I. 7G5*325 grms. of water gave 0-1936 grm. of pyrophos- 

 phate of magnesia = 0-070929 grm., or 0*00926 per cent, of 

 magnesia. 



II. 732-015 grms. of water gave 0*1837 grm. of pyrophos- 

 phate of magnesia = 0*0673 grm., or 0*00919 per cent, of 

 magnesia. 



Mean of the results, 0*00922 per cent. 



Mean of the magnesia combined with carbonic acid 0*00023 

 Mean of the magnesia contained in the water asl o*00895 



chloride of magnesium j _^_ 



Total amount found by addition 0*00918 

 Mean of the total amount found by direct estimation 0*00922 



7. Estimation of the Alkalies. 



For the estimation of the alkalies the mineral water was 

 evaporated to one-third of its volume and baryta water added 

 in excess, the precipitates of sulphates of baryta, lime, mag- 

 nesia and sesquioxide of iron were filtered off, and the excess 

 of baryta precipitated by means of carbonate of ammonia. 

 To get rid of the silicic acid the filtrate was evaporated to 

 dryness with hydrochloric acid, gently ignited, dissolved in 

 water, again filtered and evaporated to dryness ; the mixed 

 chlorides obtained in this manner were weighed. 



I. 632*481 grms. of the mineral water gave 0*2937 grm. of 

 chloride of sodium and chloride of potassium = 0*04643 per 

 cent, of the mixed chlorides. 



II. 546*032 grms. of water gave 0*2538 grm. of chlorides 

 of sodium and potassium = 0*04648 per cent, of the mixed 

 chlorides. 



Mean of the results, 0*04645 per cent. 



8. Estimation of the Potassa. 



The chlorides of potassium and sodium were dissolved in 

 a small quantity of water and an excess of bichloride of 

 platinum added ; the liquid was then evaporated to dryness 

 in the water-bath, the residue digested with alcohol, the in- 

 soluble chloride of platinum and potassium filtered off from 

 the soluble sodium salt and washed with alcohol ; the preci- 

 pitate was dried in the water-bath and weighed. 



I. 632*481 grms. of the mineral water, or 0*2987 grm. of 

 the mixed chlorides, gave 0*124 grm. of chloride of platinum 



