There are postage stamps of four values.
These " six indirect contributions " were the revenues from tobacco, salt, wines and spirits, stamps (commercial), certain specified fisheries, and the silk tithe in specified provinces.
Indiarubber stereotypes are now extensively made use of as hand stamps, and attempts have been made to introduce them for press and machine printing.
Thus, for instance, to% aluminium bronze is scratched by an ordinary steel knife-blade, yet the sets of needles used for perforating postage stamps last longer if made of aluminium bronze than if made of steel.
The empire was bound together by roads, along which there was a regular postal service; and clay seals, which took the place of stamps, are now in the Louvre bearing the names of Sargon and his son.
