Who are the kinchins? What is Noah going to do to them?

Kinchins:

"The kinchins, my dear," said Fagin, "is the young children that's sent on errands by their mothers, with sixpences and shillings; and the lay is just to take their money away -- they've always got it ready in their hands, -- then knock 'em into the kennel, and walk off very slow, as if there were nothing else the matter but a child fallen down and hurt itself. Ha! ha! ha!"