Analyses of Wafer — Dodge, 273 



2. Analysis of the mineral matter found in the water run 

 off from the boiler: 



Sulphate of lime, Ca SO4+2H2O, 

 Carbonate of lime, Ca CO 3, 

 Carbonate of magnesia, Mg CO3, 

 Sulphate of magnesia, Mg SO 4, 

 Sulphate of soda, Nag SO 4, 

 Chloride of sodium, Na CI, 

 Undetermined, 



4209.5 



COMMENTS Olf THE RESULTS OF FOREGOIN^G AN"ALYSES. 



(1). The amount of mineral matter as a whole was greatly- 

 increased by the boiler. Often the reverse of this is observed. 



(2). The increase is seen to be due chiefly to the presence of 

 sulphates. The sulphate of soda and the sulphate of magnesia 

 being very soluble salts of course remain in the water and pro- 

 duce a concentrated solution. In this case the same is seen to be 

 true to a great extent with the sulphate of lime. 



(3). Some matters were removed by the boiling process, by 

 precipitation, namely the carbonates of lime and magnesia. If 

 these alone had been present, the second sample of water would 

 have been quite soft. 



(4). A saturated solution of sulphate of lime contains about 

 3,000 parts of Ca S04+2HjO to one million of water, at tempera- 

 tures from 60*^ to 212^ Fahr. Above the boiling point less sul- 

 phate of lime remains dissolved. Hence the water in the boiler 

 may have been a saturated solution of sulphate of lime, though 

 found to be less than saturated when run off and cooled (disregard- 

 ing the effects of other salts on the solubility of this). 



Note. — Specimens of the dry residues from equal volumes of 

 the two samples of water, in porcelain evaporating dishes, were 

 shown. They exhibited a marked difference in appearance. From 

 the second sample there was a large residue with abundant crystals 

 of sulphate of lime and some of sodium chloride; from the first sam- 

 ple there was a comparatively small residue, with very few crystals 

 noticed. 



April 2, 1889. 



