60 GREEN COLOR FOR FOLIAGE. 



the connexion, that we can do little more than theorize 

 upon the subject; but perhaps I may slightly instance 

 the difference existing in the fibre of flax and silk. 

 The parts which compose the filaments of the former 

 are generally considered as being flat and flaky, where- 

 as those of the latter are tubular and round : this con- 

 formation renders silk so soft to the touch, and refract- 

 ing more perfectly the rays of light, occasions much of 

 its lustre, and the brilliancy of its hues. Perhaps we 

 have no art or trade less confined within the trammels 

 of formulas than that of the dyer ; every professor ap- 

 pearing to have his own methods of acquiring particular 

 tints and shades, guided often in his proportions by that 

 mutable sense, the taste, and regulating the temperature 

 of his compositions, not by the thermometer, but by the 

 feeling of the hand ; and so capricious are these tests, 

 so different the sensations of the operator, or the va- 

 riable influences of solar light, that success on one day 

 does not insure a similar result on another. 



Color is probably only reflected light ; but by what 

 means the "absorption of oxygen increases the lustre is 

 not quite obvious yet the power of the sun's rays, jn 

 augmenting the intensity of the hues of many things, is 

 well known : there is an admirable green color for foli- 

 age, to be obtained by the union of the light Prussian 

 blue with the dark gamboge ; but I could never acquire 

 this clear and lustrous, without compounding it in the 

 light of the sun. As the young artist will find this a 

 most useful pigment, I may in addition say, that a small 

 bit of the light Prussian, with three or four times the 

 quantity of gamboge, must be laid upon the pallet, or 

 in the saucer, and with a drop or two of water, only 

 enough to make it work easily, be most thoroughly 

 united and incorporated by the finger, with the sun 

 shining upon the mixture, adding more gamboge re- 

 peatedly during the operation, until the blue is subdued 

 and a clear green produced ; but if a tedious operation, 

 yet perseverance will ultimately produce a very brilliant 

 permanent green. 



We have our walls in many places here decorated 

 with most of the varieties of the great snapdragon (an- 



