in Agriculture. 



187 



of which equal bulks contained equivalentsj and adding equal 

 portions successively to a known quantity of a saturated solution 

 of pure chloride of sodium, taking care to mix whichever was 

 first added thoroughly with the solution before adding the other, 

 I have obtained the following results, by which it is shown that 

 a satm-ated solution of chloride of sodium dissolves j-g^^^ of car- 

 bonate of lime, or about 5^ times as much as Professor Connell 

 gives as the amount dissolved {-^^^23) ^Y *^^ common water of 

 St. Andrews. The chloride of sodium was of course perfectly 

 freed from carbonic acid before trying the experiments. 



The addition of the solutions to the chloride of sodium was 

 continued until a slight film of carbonate of lime was deposited 

 upon the mixture standing for half an hour; a deduction was 

 made for the excess added ; the numbers therefore represent the 

 amount of carbonate of lime which can be pei*manently held dis- 

 solved by the chloride of sodium. I say this, because I believe 

 that a far larger amount may be retained in solution for a limited 

 time; for if the first trivial precipitate is disregarded, twice or 

 three times as much of the two solutions may be added without 

 producing any such increase of the precipitate as ought to occur, 

 if at that stage the chloride of sodium absolutely refused any 

 further action. But this somewhat curious result I think of 

 prosecuting further. It must not, however, be supposed that it 

 is only on carbonate of lime in the nascent state (if the expres- 

 sion may be allowed) that the chloride of sodium exercises this 

 power ; if the two solutions are allowed to mix by pouring them 

 simultaneously upon the surface of the salt solution, so as to 

 produce there a stratum of recently precipitated carbonate of 

 lime, the chloride of sodium will dissolve this with the utmost 

 facility upon agitation. The clear solution may be boiled without 

 any separation of carbonate of lime occurring ; it is partly thrown 

 down by boiling with carbonate of ammonia, partly also by boiling 

 with ammonia, and apparently completely by oxalate of ammonia. 

 Whether there exists in this solution chloride of sodium dis- 

 solving carbonate of lime, or chloride of calciiun not decomposed 

 by carbonate of soda, we have no present means of determining, 



02 



