i?. S. Woodward — Iced Bar Base Apparatus. 35 



the bar On the top of each plug is ruled a fine line in the 

 direction of the bar as shown at P in the drawing. The 

 length of the bar as regards alignment is defined to be the 

 distance between the transverse graduation marks when the 

 upper surfaces of the alignment plugs are all in one plane and 



T-TEOUGH. 



Scale — J£ 



