"You ought not to think an hour upon the matter, but to spring to action at once.
The purpose of the words "hour" and "spring" is:
A) Most of the sentences contain comma splices.
A comma splice is the use of a comma to join two independent clauses. The comma is followed by a conjunction.
Two independent clauses:
1) You ought not to think an hour upon the matter.
2) You ought to spring to action at once.
conjunction used is BUT.