Government Experts Testing the Sticking Quality of Postage Stamps (Jul, 1929)
Government Experts Testing the Sticking Quality of Postage Stamps
UNCLE SAM’S experts at the Bureau of Standards are endeavoring to determine how sticky a postage stamp should be. With this object in view, a special testing apparatus has been devised. It consists of a revolving drum into which letters with stamps attached are placed and rolled over many times. So far, it has been found that envelopes will tear and wear out before the stamps come off.
Various tests have also been made with the mucilage used on the back of stamps. Some grades have better sticking qualities than others. Loss of stamps from envelopes served to bring about the investigation.