C.H. Gamsby was an explorer and surveyor. He was likely from Perth, Ontario. There is a river named after him, a tributary of the Kitlope River on the Gardner Inlet on the BC north coast where he explored in 1876.
He worked for a number of years on the CPR surveys:
http://www.rootsweb.com/~onlanark/NewspaperClippings/Spencer/PerthComingsAndGoings.htm