he
vertical perforations. In the later perforation of this issue the
distance is fixed (as will be shewn), and the distance is 20 1/2mm.,
[page 30] measuring from perf. point to perf. point across the stamp.
Any stamp differing in width to any extent more than 1/2mm. from
20 1/2mm. may therefore be set down as perforated by the single line
machine.

We have seen all the values except the 2d. rose and 1/- green
perforated by the single line machine, in practically every case the
C.C. watermark being upright, the exception being a strip of three
6d. with the sideways watermark. All the sheets with this perforation
appear to have one printer's guide dot in the centre of each side
margin.

The next form of perforating machine introduced in later printings
of the Crown and C.C. 1880 issue is known as a comb machine. The comb
machine perforates three sides of a stamp at once, and the form of the
first comb machine was arranged thus--

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The arrangement of the teeth of the comb fitted the arrangement of the
panes of the regular Colonial postage stamps printed by Messrs. De la
Rue & Co., the narrow spaced teeth in the centre marking the dividing
space between two horizontal panes.

In perforating the stamps of Gambia in the small sheets of fifteen
in three horizontal rows of five, both sides of the machine appear
to have been used, the extreme end portion of the comb at either end
running off the side margin of the small sheet. When the left portion
of the machine was being used the sheet was [page 33] inserted upright
and the top row of stamps perforated first, the effect being that the
top margin is not cut through by vertical perforations, and the bottom
row is (see plate III.).

When the right-hand portion was in use the sheets appear to have been
systematically inverted when placed in the machine. This left the
bottom margin blank and the top margin cut through. Had the sheet been
simply inverted and perforated by the same portion of the machine, as
already described, the narrow spaced teeth would have been produced on
the le