TO BOTANICAL PURPOSES. 191 



rapidly is this process executed, that twenty-five or thirty 

 drawings may be obtained in an hour, providing we are fa- 

 voured with a direct sun-beam ; if, however, we have only the 

 diffused day-light, five or ten minutes, and sometimes even 

 more, are required to produce a drawing with well-defined 

 outlines. 



If drawings of recent plants be required, specimens of pro- 

 per size should be cut, and if not too rigid, placed on a piece 

 of the paper, and kept in a proper position by means of a pane 

 of glass, as in the case of dried specimens ; but if the plant 

 be rigid, the specimens should be placed for twenty-four 

 hours between folds of blotting-paper, under a heavy weight, 

 before placing them on the sensitive paper. 



Having obtained as many drawings as are required, the 

 next thing is to fix them, so that their otherwise evanescent 

 character may not deprive them of their value. For this pur- 

 pose place them in a dish, and pour cold water over them ; 

 allow them to soak for ten minutes, and then transfer them to, 

 or sponge them over with, a solution, made by dissolving an 

 ounce of common salt in half a pint of water, to which half a 

 fluid ounce of the tincture of the sesqui-chloride of iron has 

 been added. The drawings thus prepared may be dried by 

 pressure between folds of linen, and exposure to the air ; and 

 may then be examined without danger. On looking at them 

 every one must be struck with the extreme accuracy with 

 which every scale, nay, every projecting hair, is preserved on 

 the paper ; the character and habit of the plant is most beau- 

 tifully delineated, and if the leaves be not too opake, the 

 venation is most exquisitely represented ; (this is particularly 

 the case with the more delicate ferns, as Polypodium Dryop- 

 teris). Among those classes of plants which appear to be 

 more fitted than others for representation by this process, may 

 be ranked the ferns, grasses, and umbelliferous plants ; the 

 photogenic drawings of the former, are indeed of exquisite 

 beauty. 



The fact of the object being white on a brown ground 

 does not affect the utility of this mode of making botanic 

 drawings ; indeed, I almost fancy that their character is bet- 

 ter preserved by this contrast of tint, than by a coloured out- 

 line on a white ground. Every one will be fully aware of the 

 value of this process to the botanist, in obtaining drawings of 

 rare plants preserved in the herbaria of others, and which he 

 would otherwise have probably no means of obtaining. 



If the drawing of a tree or large shrub be required, a box, 

 blackened inside, having a hole at one end about 1 J inch in 

 diameter, must be provided ; in this hole should be placed a 



