Chapter XV: name changed from "Electricity from Chemical Action and

Chemical Action from Electricity" to match
text which reads "ELECTRIC CURRENTS FROM CHEMICAL ACTION AND
CHEMICAL ACTION FROM ELECTRIC CURRENTS"

In the Table of Illustrations:
"Operating a Switchboard" changed to match caption which reads
"Operating the Switchboard"

p63. The example of Morse code given is correct for "Original" or American Morse. It has some differences from Continental or International Code which is the current standard. The spacing of the dots is significant.