120 
THE YOUNG SCIENTIST. 
a risk to use no preparation on the silk or 
satin, Wlien no preparation is used, the 
first pigment laid on the satin should be 
a body color, i.e., the paint should com- 
pletely hide the hue and texture of the 
satin. For example : vermilion is un- 
changing red, perhaps the best example 
of natural body color, and is seen to 
great- advantage in the better class of 
Japanese and Chinese painting. Use a 
white sable brush, and charge it with as 
much color as possible. When dry, you 
find a smooth, brilliant red, no matter on 
what shade of satin you have painted. 
Try the same proceeeding with rose mad- 
der, and though the color looked bright 
when wet from your brush, it dries a dull, 
nondescript hue. You are not successful, 
because rose madder (though a beautiful 
permanent red) is not a body color; 
therefore give it a body by mixing it with 
Chinese white. Do not be dismayed when 
you see that it is impossible to keep the 
ibeautiful red color after adding Chinese 
white. Go on— add more white. Ee- 
member that this mixture should be laid 
on as thickly as the vermilion, in order to 
produce a perfectly smooth surface on 
which you may paint. When perfectly 
dry, pure rose madder, painted over this 
surface will give you the, delicate red you 
need. Mixing Chinese white with greens 
causes them to assume a bluish hue. 
Counteract this by adding yellow, gam- 
boge, yellow ochre, or Indian yellow. 
White, mixed with any color or hue, is 
called a tint. It is im])ortant you should 
use Chinese white only, because that is 
permanent, and white is the foundation 
of all tints. Use a bone stiletto, ivory 
paper-knife, horn palette-knife, or wooden 
brush handle in mixed colors, as many 
colors are injured by contact with steel. 
The exception to the general rule of lay- 
ing on the color as thickly as possible is 
this : When you wish to give the effect of 
white flowers in shadow, as the semi- 
transparent appearance which is the 
characteristic of many flowers, add water 
to the Chinese white till it is almost 
liquid, and by painting this quickly over 
the satin, the color of the material, show- 
ing partly through the thin white, pro- 
duces a grayish effect of exceeding deli- 
cacy and beauty. Colors bought in pow- 
der' are better adapted than moist or cake 
water colors for painting on silk and 
satin, or, indeed, any textile fabric. Pow- 
der colors, such as used for wax flowers, 
are fine enough for you to mix with Chi- 
nese white and gum-arabic. Mix by 
grinding all at once with small glass mul- 
ler or the bottom of a small glass bottle. 
The reason that powder colors are used 
by the French painters of fans is, because 
tliere is more body than when the paint is 
mixed by the machinery of the profes- 
sional color maker. Yehicles.— No mat- 
ter how finely you grind powder paints 
with water, something more must be 
added to keep the colors from rubbing off 
as soon as the water has evaporated. 
Whatever may be successfully used to fix 
paints is technically termed a vehicle. 
The difficulty to be looked out for is this : 
If the satin be neither white nor black, 
some color has already been used on the 
texture, which may be aftected by some 
of the vehicles which are easily used on 
white paper ; therefore try a small piece 
of satin before deciding which vehicle is 
to be used. Among the vehicles that have 
been most used in painting on silk are 
gum-arabic, gum ammoniac, gum traga- 
canth (so often found in a grandmother's 
paint-box), starch — domestic— but posses- 
sing valuable properties in the prepara- 
tion of paper, as well as textile fabrics — 
rice water, flour i:)aste, the white of an 
egg (the chief size used in mediaeval mon- 
asteries j and white castile soap. The 
most useful, with the least deficiencies, 
is gum-arabic. It should be bought in 
lump, and not in powder. Dissolve in 
cold water, strain through a white mus- 
lin, and keep in a wide-mouthed bottle 
(with a cover) by your side while paint- 
ing. Mix your paints with this, instead 
of simply water, if you are using moist or 
cake colors. Gum-arabic is best dissolved 
fresh each day, because this, like all 
other gums, contains an acid which acts 
against the preservative qualities of this 
gum in a liquid state. If it is inconven- 
ient for you to mix fresh every day, 
then add a little alcohol to the gum- 
arabic, or counteract the action of the 
acid by an alkaline substance, take 
one scruple of carbonate of ammonia 
to an ounce of gum, dissolved in three 
ounces of water ; shake the mixture well. 
The carbonate will purify the gum-arabic, 
preserve it for long use, and cause the 
paints to work more smoothly. Gum 
ammoniac, dissolved in water, forms a 
milky fluid that dries transparent. No 
fly of insect of any kind will approach 
the satin if this gum is used in mixing the 
paints. And in this respect ammoniac 
has a great advantage over colors mixed 
with honey or sugar- water. It also gives 
a gloss to the colors, and acts somewhat 
like a varnish over the water colors. Gum 
tragacanth, dissolved in hot water, is use- 
ful when the paint is not to appear glossy. 
Starch, made as if for household use, and 
used only when made fresh each day, is a 
good working vehicle. Rice water is used 
by the Chinese to mix their colors. It 
must be remembered that their brilliant 
imitations are painted on rice-paper. 
Flour paste, made without lumps, makes 
a cheap and convenient vehicle for the 
mixture of colors. The white of an 
egg is perhaps the most venerable vehi- 
cle for paints; the yolk has been used 
