and Laboratory Methods. 



2655 



from other points of view than profile. In default of these, all the manifest 

 results were apparently inconsistent and anomalous, and pointed to a greater 

 complexity in the problem than was at first anticipated. After some trials a 

 magnifying power of about 2S0 seemed desirable to show all the important 

 details. In the accompanying photomicrographs, the line of the edge sonie- 



FiG. 4. 



times shows, or, if taken somewhat obliquely, the center of the edge-band. 

 Above this line a continuous wire-edge may appear (Fig. 5), or a remnant of it 

 as a large grain near the middle (Figs. 3 and 4). Below the line the scratches 

 of the hone are seen on the face of the chisel. 



A little study of the edges also suggested that the thorough investigation of 



Fig. 5. 



the effects of each hone on the chisel edges would require examination of each 

 edge on three planes or sections, viz.: vertical, horizontal and transverse. 



I. VERTICAL SECTION, 

 i. e., from side view of edge in profile, as when either fiat side of chisel is held 



