THEORY OF CHURNING. 431 



known facts. By microscopical examination of cream during 

 churning the formation of nuclei of irregularly shaped masses 

 of fat globules is noticed. As an irregular mass will occupy a 

 greater apparent volume than a sphere, the transformation of 

 spherical globules into irregular nuclei should be attended with 

 thickening of the cream, which is in accord with the facts ; as 

 the nuclei increase in size, the layer condensed by surface energy 

 round them will rapidly become less, so that the cream will 

 gradually decrease in thickness ; this decrease in thickness of 

 the cream should take place later than the increase mentioned 

 above, which is also the case. 



When the butter is taken from the churn it is in fine grains 

 which are the nuclei referred to. On working, the fat globules 



Fig. 50. Butter Worker. 



are brought still closer to each other, and the butter is formed 

 into a nearly homogeneous mass ; small amounts of liquid are, 

 however, left distributed throughout the mass, and as these 

 liquid globules are very small and contained in a medium which, 

 though solid, is still viscous, they are by surface energy trans- 

 formed into spheres. The microscopical examination of butter 

 shows a number of spherical globules of aqueous liquid in a 

 nearly homogeneous medium consisting of fat ; there are, how- 

 ever, many fat globules left, which, by careful examination with 

 little light (best by dark stage illumination), can be made out. 

 The whole of the globules usually seen, which are of all sizes, 



