76 THE HOUSE I LIVE IN. 



N 



There are, however, no wheels here. There 

 is indeed something like a mill, and it performs 

 some grinding ; but the motion by which this 

 grinding is performed is much like that of a 

 pestle in a mortar. One of the segments of a 

 wheel, with its cogs, stands still during the 

 operation, while the other moves up and down 

 upon it, and breaks in pieces the substances 

 which come between. It also slides a little to 

 the right and left, on the other, and thus per- 

 forms its grinding process. 



Look now at the engraving. This repre- 

 sents the left side of the bones of the human 

 face, as it would appear if the outside of both 

 the upper and lower jaw were split off. 



