HISTORY OF BOTANIC ILLUSTRATION. 
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from the ‘ Kwa-wi ’ by Yonan-Si. My last example of modern 
wood-engraving is Conhim maculotum , by Fagcet, in Baillon’s 
‘ Dictionnaire.’ You will notice the admirable production of aerial 
perspective, by which the nearer portions stand out from those in 
the background. 
Now we arrive at the second period of copper-plate engraving, 
or, as more often, steel, to withstand the wearing down of the 
plate by the hand of the workman when cleaning it in printing. 
The method of stipple was used by P. J. Redoute, in a series of 
volumes which both for design and execution stand unapproached. 
The basis of his plates was stippling, a series of dots, and this 
plate was printed in colour by charging the various parts of the 
engraving with its appropriate pigment, the leaves green, the 
roots brown, the flowers yellow, etc., and then uniting the whole 
by high finish in water-colour. Of this I can give you no example; 
but the next slide will display quite as exquisite work in black 
and white, a plate from Thuret’s ‘Etudes Phycologiques’ (1878), 
in which you see that the full strength or colour of the alga is 
given, with extreme delicacy of the other parts; in fact, though 
the delicacy can be appreciated on the plate, the camera fails to 
do it justice, and I have therefore brought a second slide from 
another plate, for the delicate work alone. 
3. Lithography. —The effect of the last slide leads naturally 
to the subject of lithography. Here we do not employ difference 
in level to bring out the design. The drawing is made on the 
smooth surface of a limestone from Solenhofen ; the stone is 
either quite smooth, when a greasy ink is used, or a grain either 
coarse or fine is given by sand and water to receive lithographic 
chalk, so-called, a mixture of f;it, soap, and lamp-black. The 
peculiarity of the stone used is, that while it absorbs either grease or 
water with ease, each repels the other, so that after treatment with 
weak acid the stone will receive ink on the design but not on the 
wetted parts of the stone. Lithographic printing therefore consists 
of inking and wetting the stone between each impression, the 
process depending on the impartiality of the stone for either, and 
the mutual repulsion of the ink and water. Here is an instance 
of a lithograph of Cinchona by J. N. Eitch, after a drawing by 
Riocreux which was intended to have been engraved in Paris, 
but this English draughtsman succeeded in producing the desired 
effect by lithography. For work of great minuteness the stone 
is often engraved, a ground being spread over the stone, and lines 
cut through the ground with a diamond. 
Thus far we have had to do with illustration which depended 
