“A counterclaim, to quote from Halsbury’s Laws of England (3rd ed.) Vol. 34, p.395, para. 671, is -“A weapon of offence which enables a defendant to enforce a claim against the plaintiff as effectually as in an independent action.” Instead of suing separately, the defendant may insert his claim into the plaintiff’s suit under the label of counterclaim if it is of a kind which by law he is entitled to raise and have disposed of in the plaintiff’s suit.”