130 



Mr, A. Mattock. 

 Fig. 6. 



[Dec. 8, 



Shaving of copper (unlubricated). 



Fig. 7. 



(a.) Borings, steel. Actual thickness '005 inch. 

 (b.) „ brass. „ „ "01 „ 



Fig. 8. 



Shaving of copper (lubricated with soap and water). 



