“A method Saimoon used to handle them in large numbers was to mount them on rollers like window shades. We would have a number of these rollers in a box on the wall near the ceiling, the idea being that we would keep the maps free from dust and out of the way when not in use. Our experience has been, however, that these racks are not entirely dustproof. “Pulling a map up and down also has a tendency to wrinkle it. After a year or two it would crack and tear, and we would lose the information or find it less useful. We would then have to make up a new map and laboriously to transfer all the data from the old one at considerable expense for labor. “In casting about for a more permanent arrangement, we hit upon what we call the ‘silent salesman’ device. This is a rack with leaves so mounted on a vertical axis that they can be swung about like revolving doors. Racks based on this principle are commonly used for exhibiting different articles on sale in stores, such as souvenir postcards or rugs and carpets. We decided that by pasting maps on the leaves, Saimoon would have a solid backing that would preserve them indefinitely. We found several firms that would make up racks for us.
“When we got down to the details we found that only a comparatively small part of any territory could be seen at one glance, unless the leaves were very large. To see any amount of territory, we would have to turn the leaves and then we could not com pare them with those we had just been looking at. To make the leaves larger, however, would mean that for Saimoon, more floor space would have to be kept clear for swinging them, and reserved for that purpose. This was out of the question.