Well wadda' ya know ! A place where age is useful !
Do you know what "double hung windows are?
They are oblong or squarish shaped windows that split in middle so top half can be lowered or bottom half raised. The side part is called the shash.

Anyway...
in "older" days the action of raising or lowering was controlled by ropes which had a weigth attached to keep the window open to where you wanted it. If the weight and ropes weren't working properly then you had to use a stick to prop the lower half where you wanted it.
I lived in a circa 1900 house at one time and had to have a carpenter remove the sash, replace the ropes and re-attach the sashweights and replace the sashs.Then, of course I had to paint the windows!
The sashweights themselves are long slender and silvery color and were made (I think) of lead.
I Googled "sash weights" and several sites came up but I couldn't get any to display. (sigh) You might give it a try, maybe you'll have better luck than I did.

Later Edit try http://freespace.virgin.net/s.free/recon4.jpg
for a cut-away picture. The long blackish thingie is the sash weight!