EXTRACT S — F OREIGN AND DOMESTIC. 339 



the other half finally resists ; that with others, only one-third, or 

 less, is dissolved. 



The principles of the ashes of plants which are soluble in cold 

 water, are formed, without exception, of salts with alkaline bases 

 {^pofassa and soda) ; those soKible in the acids, are salts of lime 

 and magnesia. The residue insoluble in the acids is silica. 



The unequal portion of these principles, which are so different 

 in their mode of acting with water and the acid, enables us to di- 

 vide plants in culture into plants containing potassa, which con- 

 tain more than half their weight of soluble alkaline salts ; into 

 plants contahiing limej in which the calcareous salts predominate ; 

 and into plants containing silica, in which there is a predominance 

 of silica. These are precisely the principles which are necessary 

 to them in very great quantity for their development, and which 

 essentially distinguish them from each other. 



[Continued from number 1, page 137.] 



|EXPERIMENTS AND OBSERVATIONS ON THE PRO- 

 DUCTION OF BUTTER. 



BY PROFESSOR TRAILL. 



Series 1. 

 I The comparative value of the first and last portions of the milk. 



For this purpose a cow was selected which had calved five 

 weeks before, and the experiments were begun on Monday, 26th 

 May, 1806. 



No. 1 was the first pint milked. 



No. 2 was a pint of the whole milkingy after the separation of 

 No. 1 and No. 3. 



No. 3 was the last pint of the milking, or afterings. 



As in previous experiments, scalding the milk was found to 

 favor the more perfect separation of the butter, after the three 

 portions were allowed to remain twenty-four hours in the milk- 

 house. They were at the same time placed in earthenware basinSy 

 in a pan of water heated to 180° Fahr. They were removed with- 

 in an hour from the water, when the milk had acquired a temper- 

 ature of 130°. They were replaced for ten hours in the milk- 

 house, and then examined. No. 1 then showed scarcely any indi- 

 cation of cream. It formed a very thin pellicle only; and the 

 quantity, being too small to be churned, was estimated from other 

 :omparative trials, to be no more than equivalent to five grains- of 



