ON CALCAREOUS EARTH 247 



provided some body be mixed with it to prevent its fusion. 

 Neither will his opinion that, in the distillation of crude 

 calcareous earth (Experiment 3), the phlogiston it contains 

 passes over along with the moisture and precipitates the 

 lime-water in the receiver, easily find admittance. Will any 

 reflecting chemist readily suffer himself to be persuaded that 

 pure phlogiston parts from a body, without at the same time 

 being in immediate contact with another body for which it 

 has a stronger attraction. We cannot show that water has 

 the smallest disposition to attract phlogiston, considered in a 

 state of purity ; and we find, in general, that acids must be 

 employed as the means of effecting such a union. The 

 theory of Dr. Black explains this precipitation so clearly, 

 that nothing can be objected to it. When the author allows 

 the lime-water to remain in the receiver to the end of the 

 process, while there is at the same time an excess of chalk 

 in the retort, he finds that the lime-water redissolves the 

 regenerated calcareous earth. Now, if we assume with him 

 that phlogiston in excess can dissolve even crude calcareous 

 earth in water, his phlogiston must either be an acid or not 

 an acid ; in either case a few drops of nitrous acid must 

 precipitate the solution (he must grant this, as, according 

 to his first experiment, nitrous acid is capable of attracting 

 it from lime in the fire) ; but no such thing happens. I 

 have scarce any inclination to advert to the 4th experiment, 

 as it contradicts all experience. The fixed air expelled by 

 nitrous acid from a quarter of a pound of calcareous earth, 

 does not precipitate more that 1 qt. of lime-water. In the 

 5th experiment, the author precipitates lime-water with an 

 alkaline spirit obtained from horns; but finds that the 

 earth, after it has been dried, is lighter than the lime 

 employed. It cannot be unknown to the author that the 

 fixed air separated from the alkaline spirit during the 



