156 



SEPARATION OF CREAM 



same way as in the gravity system. This method of separation, 

 according to J. H. Monrad,' had its origin in 18O4. As early as 

 1859 Professor P\ichs of Carlsruhe, Germany, suggested testing 

 the richness of milk b}- swinging tubes holding the samples of 

 milk. In 1S64 Prandtl, a brewer of Munich, separated milk by 

 such a device. In 1S70 Rev. F. H. Bond, of Northport, Massa- 

 chusetts, worked out a method of separatitm which consisted of 

 two small glass jars attached to a spindle making 200 revolutions 

 per minute. By one hour's whirling the cream was brought to 

 the top. 



.In 1875 Prandtl exhibited at Frankfort-on-the-Main a con- 



^AT^" 



Fig. 46. — First centrifugal separator. (From Dairy ]\TessenRer.) 



tinuous separator, which did not at the time attract much atten- 

 tion, due chiefly to the excessive amount of power needed to 

 overcome the resistant force of the air. In 1S76 a Danish engi- 

 neer named Winstrup succeeded in improving the old bucket 

 method. In 1877 Lefeldt and Lentch offered for sale four con- 

 tinuous separators with different capacities (from no to 600 

 pounds of milk per hour). During that }-ear also, the first 

 practical centrifugal creamery was established at Kiel, t^iemiany. 

 In 1877 Houston and Thompson of Philadeljihia filed a j)atent for 

 the continuous method of separation of cream fiom milk. The 

 patent was allowed in i8qi. In March, 1877, Lefeldt and Lentch 



'Dairy Messenger, Oct., 1802, p. log. 



