470 ANALYSIS OF THE 



the force of cohesion, in determining the combination of the 

 ingredients which form the least soluble compomid. If a dif- 

 ferent mode of analysis were had recourse to, if the whole lime, 

 for example, were precipitated by any re-agent, there would 

 still remain the uncertainty with what it had been combined, 

 whether entirely with muriatic, or partly with sulphuric acid ; 

 and there is no mode of determining this, by obtaining the 

 other product of the action of the re-agent, which would not 

 be liable to equal ambiguity ; or, if the sulphuric acid were ab- 

 stracted by a re-agent, there would equally be the uncer- 

 tainty, whether it had been previously combined with soda or 

 lime. 



If sulphate of lime did not separate when the water was re- 

 duced by evaporation so fai-, that, from the known solubility 

 of the sulphate, the precipitation of it ought to take place to a 

 certain extent, it might be concluded that it did not exist. 

 Yet even this conclusion, were the fact found to be so, (which 

 it is on making the experiment), is invalidated by the result, 

 sufficiently established, that salts, by their mutual action, of- 

 ten increase the solubility of each other, and the sulphate 

 of lime might, from this cause, be retained dissolved, in a 

 smaller quantity than it would require by itself for its solu- 

 tion. 



One kind of proof may be given, that of shewing, that a 

 much larger quantity of sulphate of soda, than what analysis 

 indicates in this water, may exist in it, without any precipita- 

 tion of sulphate of lime. I added to different portions of the 

 water (four ounces each) 5, 10, 15, 20, and 30 grains of sul- 

 phate of soda. In none of the experiments was there any im- 

 mediate effect, and even after twenty-lour hours, there was no 

 turbid appearance, or apparent change. In the greater num- 

 ber of these proportions, the quantity of sulphate of soda was 



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