THE HINGES. 87 



There are indeed a few parts of the house I 

 occupy, which are not intended to move much ; 

 but in general it is not so. Even the girts, 

 braces and studs, are designed to regulate and 

 direct motion, but not to prevent it wholly. 

 And the joints, instead of being framed together 

 by means of square tenons and deep mortices, 

 and kept as dry as possible, are rounded and 

 made smooth, and moistened by a sort of oil, 

 to fit them for motion, rather than to hinder it. 



There are indeed a few joints if joints they 

 ought to be called which are firm and un- 

 yielding. I refer to the teeth. These, as we 

 have seen, are set into the jaw bones, as firmly 

 as tenons are into mortices, and more so. 

 They seem to stand more like nails or spikes, 

 when they are driven into planks or timbers. 

 The bones of the head, too, are joined firmly 

 together in adults, as you have already been 

 told. 



Some of the joints of the human frame are 

 real hinges. To this class belong the knee 

 joints, the joints of the toes and fingers, and 

 those of the elbow. The lower jaw may also 

 be called a hinge joint. The ankle joints, the 



