Having duly considered the design, printing and paper of stamps, the next thing to attract our attention is the gum. Most gums are prepared from potato starch, dextrin or gum arabic. Gelatin is sometimes added to supply body and glycerine to give smoothness. Gum varies much in thickness and color. The first three cent stamp of the Danish West Indies furnishes an instance of this. The stamps were sent from Denmark without gum, as is frequently done with stamps for tropical countries. When they reached the islands the stamps were given to two druggists to be gummed. One used gum of good quality and, light color, while the other used poor material and of so dark color as to stain the paper and even darken the ink of the stamps. In Hanover rose-colored gum was used for a number of issues. Some of the earliest local prints of the South African Republic were made upon paper sent out ready gummed from Germany. The paper was much wrinkled by the gum and the effect may be seen in the wavy and broken lines of the ink. The stamps of the first issue of Reunion were sold ungummed and were affixed to letters in any way that pleased the writers. Some were fastened by wafers and some even were pinned on. Formerly, sheets of stamps to be gummed were fastened in a frame and the gum applied by hand with a large brush. They were then sent to the drying room and hung up to dry. Now the process is entirely mechanical. The sheets are fed into a machine in which they first pass under a gummed roller. Then they are carried on an endless chain through a long box filled with steam pipes and emerge at the further end dry and ready to be pressed and perforated. The subject of perforations is also worthy of some brief attention. The first stamps were imperforate, necessitating the use of scissors or other instrument in separating them. This was a manifest inconvenience. In 1847, Henry Archer, an Irishman, began experimenting with machines for perforating stamps. After a number of attempts he succeeded in making a machine which was accepted by the English government and for which, in 1852, he was allowed a compensation of L4,000. James M. Napier greatly improved on this machine and adapted it for steam power.