ERRATA 
Page v—Right hand column, 6th line from bottom: 
For “A 2729" /p(6.35 10-5)”, read “A 229" /p(6.35 10-9)” 
Page 15—Right hand column, 3rd line of equations from top: 
“id. ” igs d6é”’ 
For “ag” read “dp” 
Page 17—Right hand column, 5th line of equations from top: ° 
26 ” 
Bat ry 
Page 18—Left hand column, last line of equations: 
= “ VB ” c BVa ” 
Bor TFati—a) 4 TF all) 
Page 29—Left hand column, 30th line from top: 
For ‘‘2 feet’’, read ‘‘2 meters”’. 
Left hand column, 34th line from top: 
For ‘0.9 feet”’, read “0.9 meters” 
For fs dp 2be= 0 ie ceadt 
vI 
