This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
When the putty becomes loose and the glazing points work out on window glass, temporary repairs may be made by using a small piece of tin or sheet iron bent as shown in the sketch. The clip is inserted under the edge of the glass and hooked over the back of the sash parts. This will hold the glass firmly in place and also prevent rattling.