210 CHYMISTKY APPLIED TO AGRICULTURE, 



ARTICLE IL 

 Of Butter. 



I HAVE already remarked, that there exists between the 

 Gonstituent principles of milk but a very feeble affinity: 

 rest alone is sufficient to produce the separation of them 

 in the course of a few hours, when the butter which exists 

 in very minute particles in the milk, rises to the surface with- 

 out any approach towards forming a solid body. In order to 

 bring butter into a solid state, it is necessary to disengage 

 from it all the other principles which it carries with it : this 

 is done by means of churning. 



It has been clearly proved that the quantity of butter pro- 

 duced from the milk of a new milch cow, is less than is 

 yielded by the iriilk of the same cow five or six months after 

 calving. It is likewise well known, that if cream be re- 

 moved as fast as it is formed, the butter made from the first 

 layers will be more delicate than that from the last. Milk 

 that has remained a long time in the udder, furnishes more 

 butter than that which is drawn as soon as it is secreted : 

 thus milk that is drawn from a cow but once a day, will yield 

 one seventh more of butter. 



Milk obtained at the same milking presents similar differ- 

 ences ; the portion which is drawn first, is thinner and more 

 watery than the last drawn, and it yields less butter. 



All these facts,, ascertained by experiment, are capable 

 of being extensively applied both in medicine and rural 

 economy. 



The particles of butter contained in cream, cannot be 

 separated from the milky portions with equal ease, at all 

 seasons of the year, or at all degrees of temperature ; the 

 operation of churning requires much m.ore time in winter 

 than in summer, nor can the process be shortened except- 

 ing by enveloping the churn in a hot cloth, or by plunging it 

 into hot water ; hot milk is sometimes added to the cream ; 

 but all these means affect more or less the good qualities of 

 the butter. 



During the heat of summer, it is necessary to set the cream 

 in a cool place, and to churn at those hours of the day that 

 are coolest ; in some countries, it is customary to place the 

 churn in very cold water. 



The butter made in some countries, and which is thought 



