Ko. UL] 187 



without curdling, hard water curdles it at once ; for the reason that iti 

 its passage through the earth it has dissolved one or more of the neu 

 tral salts which it holds in solution. If for instance, that salt has 

 been sulphate of lime, which consists of sulphuric acid and lime ; and 

 soap consists of alkali, either soda or potash, oil or fat, the alkali 

 uniting with the fat forms soap, part of which is soluble in water, 

 viz:, the alkali, but the fat is insoluble, when soap is placed in water 

 containing this sulphate of lime, which has a stronger attraction for 

 the alkali than it has for its own lime, releases the lime and takes pos- 

 session of the alkali, consequently the fat is immediately released, 

 and the soap separates into its original parts, alkali and fat, and is no 

 longer soap, I would not desire you to understand that the soap is 

 of no use in the hard water, for to a certain extent you can wash with 

 it, for the reason that water rarely dissolves so large a portion of sul- 

 phate of lime, as to entirely destroy the action of soap ; pure water 

 is not injured by coming in contact with lime stone, carbonate of limcj 

 chalk, &c., for the reason that they are insoluble in water. 



If such was not the case, we should have very little pure water in 

 the world, as this species of earth is one which abounds in nature. 

 Do you know the reason why all your boilers and tea-kettles become 

 coated with a hard whitish substance, which in time if your house- 

 keeper does not frequently examine will clog up the spout in such a 

 manner that the water will not issue forth*? it is because water in its 

 percolation through the earth, comes in contact with carbonic acid 

 gas, which it has a great affinity for, and instantly absorbs, thus hold- 

 ing an abundance of this species of lime in solution j by boiling the 

 water the carbonic acid is driven off, and the lime is converted into a 

 bi-carbonate. If the boiling is continued for some time this bi-car- 

 bonate is reduced to common carbonate, which is not at all soluble in 

 water, and this substance is precipitated to the bottom of your tea- 

 kettle, where it remains unacted upon, and daily increases in bulk, 

 until it finally chokes the spout. If any of you desire to find out 

 whether your wives are good housekeepers or not, examine on your 

 return home to-night their tea-kettles, and if you discover a hard crust 

 of unin-^-iting matter lining the same, be assured a recent examination 

 has not taken place. 



Thus carbonic acid gas issues from the earth constantly in large 

 quantities. I visited while in Italy the famous Grotto del Cane, a 

 few miles from Naples, where ihis gas rises in such quantities as to 



