pane at a time, but these are very rare. In the latter case, the sheets being divided into four panes of 80 stamps each, the surcharge is applied in two operations, so that the two top panes are similar and differ from the two bottom panes. It follows, therefore, that the finding of one error in a sheet of paper with the elephant's head watermark indicates that another of the same kind exists in the same sheet.
If stamps are required for service purposes, an additional surcharge (except in the case of Gwalior) is made in the same way on the requisite number of sheets of surcharged ordinary stamps. The result of this additional surcharge being made separately is that the interval between the word "Service" and the name of the State, as well as its general position on "the stamp varies greatly. This will also explain how the "service" surcharge is sometimes found inverted, an accident which is due to a sheet having been fed into the Press upside-down for this second surcharge.
