128 DE. W. G. DUFFIELD, MESSRS, THOS. H. BURNHAM AND A. H. DAVIS OX 
For example, in fig. 15, .Series B, instead of 0'45 dynes being the pressure at 
5 amperes it is I'O dynes, since if produced backwards the curve cuts the vertical 
axis at —5'5 dynes. 
The curves for Series B have been represented by straight lines wherever possible, 
but it is obvious that the points are often better represented by curves slightly 
convex to the current axis; they are subject to the same corrections as Series C, 
and they become more nearly straight after allowance is made for convexion 
currents. 
In Table X. are shown the values of the pressures corrected for convexion currents 
for arcs of 10 amperes and 6 mm. length. We shall make further use of these values 
in a later section. 
