42 
THE YOUNG SCIENTIST. 
violet and green light, and yellow of red 
and green; or we can combine yellowish- 
green and violet, and so on. 
We have seen that white light may be 
produced by combining two colors; two 
such colors are called complementary 
colors, and the study of complementary 
colors is of great importance to the artist. 
The complementary color of red is bluish- 
green ; of orange, sky-blue ; of yellow, 
violet-blue ; of violet, greenish-yellow ; 
of green, pink. There are certain laws of 
harmony and contrast in color, wliich the 
artist must know. Simple contrast exerts 
an important influence, since it heightens 
the effects of colors, if complementary. 
Thus green appears brightest by the side 
of red, or violet beside yellow; but if 
mixed, such colors destroy each other, 
producing grey. Two colors, not comple- 
mentary, if placed side by side, diminish 
each other's effect. If two colors are 
placed side by side, each will be modified, 
as if mixed with the complement of the 
other. Thus, if red and blue are placed j 
together, the blue will receive a tinge of j 
green, the complementary of red, wdiile' 
the red will receive a tinge of orange. It 
is by this contrasting of colors that the 
artist produces his most subtle effects, 
lowering or strengthening one color by 
working upon its neighbor. The light in 
Avhich we view a color affects it; blue 
drapery under the cold light of the 
northern sky is heightened by the light ; 
but if the light is orange, as from a bril- 
liant Southern sun, the blue is bluer in 
the shade than in the light. 
A tasteful person will always observe 
these principles, and, in dressing, com- 
bine colors which enhance each others 
effect. A rosy face is made still fresher 
by a green dress or bow; a green dress 
looks well with a red scarf; but no one 
would ever wear a purple dress with blue 
trimmings, or throw a scarlet shawl over 
a crimson dress. 
We will only pause to consider two facts 
previously stated. We have seen that 
yellow and blue light produce white when 
mixed, and yet we know that if we mix 
3^ellow and blue paints we get green. To 
explain this we must remember that these 
paints consist of more or less ti-ansparent 
particles, and the light which comes from 
them to our eyes is reflected partly from 
their inner surfaces, or from the paper 
below. They produce, therefore, the same 
effect that would be produced by looking 
through a piece of blue glass and a piece 
of yellow glass together. The blue glass 
is transparent only to green and violet 
rays, with their resultant, blue ; while the 
yellow glass transmits only red and green, 
with their resultants, orange and yellow ; 
hence only the green light can pass 
through both. 
The second fact is that the same object, 
illuminated by the same light, may appear 
of different colors to our eyes under dif- 
ferent conditions. 
If we look steadily for one or two min- 
utes at a bit of bright red paper on a white 
background, and then quickly remove the 
red paper, we perceive a bluish-green spot 
on the background, which to the eye, in 
its normal state, would have appeared 
pure white. We have fatigued the red 
nerves, and when suddenly exposed to the 
white light they fail to act, hence the sen- 
sations of green and violet light only are 
produced. If Ave fatigue the violet and 
green nerves by looking steadily at a 
bluish-green spot, and then quickly look 
at the purest red color of the spectrum, it 
will appear of a i)urer red than we can ob- 
tain in any other Avay. Employing this 
principle, the artist can give a green tint 
to a white spot on his paper by surround- 
ing it Avith red. 
Curious Experiments With Fire. 
IN a former article Ave showed how water 
might be boiled in a paper vessel by 
simply holding it over a lamp or candle. 
In this case, however, the paper is thin, 
and the Avater carries off the heat so 
raj^idly that the outside ncA^er has time to 
get hot. If we Avere to make a large 
vessel, capable of holding several gallons, 
of a material like paper, it would be so 
thick that the heat would not pass 
through it quickly enough, and the out- 
side would burn while the inside was 
cold. • Try to boil water in a wooden pail 
by holding it over a flre, and see what 
poor work you will make. But the In- 
