PREFACE TO THE ILLUSTRATED (FOURTH) EDITION. 
Nature. The actual fronds of the Ferns to be 
represented were mounted on cards, and pho- 
tographed the requisite size for the pages of 4 The 
Fern World.’ The photographs were transferred 
to the stone blocks of the lithographer, who by 
this process could not fail to obtain perfectly 
accurate representations of the Ferns themselves. 
The Fern figures in the present volume have 
been obtained by an equally accurate and 
faithful process, although the manner of repre- 
sentation is different, no colouring or veining 
—as in the case of the ‘The Fern World’ 
being attempted. The fronds here represented 
were laid upon white card-board, grouped in the 
manner shown in the plates. By a slow and 
laborious process their actual impress was taken, 
and the identical figures thus obtained were photo- 
graphed on the blocks of the engraver, who thus 
had before him the identical images which were 
to be marked in by his graving tools. It is due 
to Mr. J. D. Cooper, to whose direction this work 
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