No Springs

PHOTOGRAPHER'S JOURNAL: What does silk weigh? Unlike most cloth which is sold by the yard, silk is bought and sold by the pound. The silk worm which secretes the thread also secretes a gummy substance which helps to bind the cocoon in place. The manufacturers who buy the raw silk must remove this paste in order to make silken thread from which fabric will be woven. They paid for the gum discarded, and they viewed the loss in weight as lost profit.  In order to recoup that loss, manufacturers took to soaking the raw silk in metallic salts of tin, iron, or lead. These readily bonded with the silk and returned the lost weight and sometimes more.  However, the salts also caused the silk to wear badly and become brittle in time. 

Even without silk manufacturers weighting their product, the weight of silk changes significantly with humidity so product weight was always somewhat subjective. Of course, in a business based upon the weight of the product, it's not a surprise to find a precision scale such as this just outside Shipping & Receiving to assure weights are accurate and profits are maximized.