THE YOUNG SCIENTIST. 
119 
In the case of a small breakage, the 
professed moulder sticks on the piece 
with a little shellac dissolved in spirit, 
which he keeps by him in a bottle. This 
is the quickest way of mending. But it 
may be done quite as effectively and more 
neatly with a little liquid plaster, mixed 
thin 
For stopping holes of any kind, plaster 
must be mixed in the ordinary manner, 
and then "killed;" that is to say, you 
must allow it partially to set, and then 
beat it up with a little more water. With- 
out tills precaution it would set harder 
than the surrounding parts of the cast, 
and be easily distinguished from them in 
appearance. 
In the next paper I shall speak of the 
few simple tools used in casting, and give 
a brief description of wax moulding and 
piece moulding, and the methods to be 
followed in making elastic moulds, and 
taking castings from natural objects. 
Painting on Silk or Satin. 
r is more prudent to begiu paint- 
ing on satin, as its smooth sur- 
face presents fewer difficulties 
than the texture of silk. The 
objection to painting on satin is this : ttie 
gloss of the surface is exceedingly trying 
to the eyes ; so much so that, during the 
past two years several professional paint- 
ers have been compelled to give up deco- 
rating any materials except canvas or 
paper. Tlierefore, do not face the light 
while painting; wear a shade — such 
shades as wood engravers use. You must 
test the kind of satin to paint on your- 
self, by trying a sable brusli thick with 
Chinese white on a small sample. If the 
satin surface is easily moved by your 
brush, then give that piece up, and paint 
on a firmer woven kind. It is poor econ- 
omy to paint on cheap satin. Keep the 
satin firmly and sniootlily stretched on a 
drawing board or pasteboard with artist 
thumb tacks, because these tacks make 
very tiny holes, and have large flat heads. 
If you are accustomed to tlie use of oil 
paints, then begin by squeezing out the 
tube colors on blotting-imper, because 
the paper will quickly absort3 the oil with 
which the paint is mixed, and therefore 
prevent an ugly, greasy stain on the 
satin. The paint, not the material, is 
prepared. It may take your painting one 
week or more before the satin is perfectly 
dry. This is one objection to painting in 
oil. The chief advantage is that as damp- 
ness will not affect it, rain does not ruin 
the costume painted with colors. To pre- 
pare the silk or satin for painting, sinrply 
lay on ox-gall Avith a brush over the place 
which your design is to cover. The ox- 
gall is used to overcome the oily, greasy 
nature of paint mixed with oil. Use 
plenty of paint. Choose a bold design. 
Avoid the embarrassments of Nature's 
wealth of leaves. Selection, not servile 
imitation of Nature, is the only broad, en- 
during, and therefore safe rule, in design. 
In selecting a design, remember the flow- 
ers and leaves must not hide each other. 
The leaves should not be represented in a 
mass, because, from the nature of the 
material on which they are painting, it is 
impossible to give all tJiose wonderful 
gradations of color with which a ray of 
sunlight illuminates the weeds in a coun- 
try road. Decorative art does not attempt 
the impossible ; its rules simply save you 
from the blunders committed during the 
infancy of the human race. Black satin 
is the easiest to begin on, as far as your 
design is concerned, because this black 
background brings out your slightest 
effort. Black harmonizes colors. At 
lirst, aim at only three distinct hues in a 
leaf: 1st, for general color; 2d, for the 
shade ; 3d, for highest light. By hue is 
meant such a combination of cinnibar, 
green and burnt sienna as you would 
blend witli a palette-knife, to represent 
tlie leaf of the trailing arbutus, for ex- 
ample. Blend only with your palette- 
knife on your palette ; to make the paint- 
ing effective, no blending must be at- 
tempted on the satin. The same rule ap- 
plies to silk. Black is the easiest for a 
beginner. If possible, arrange your de- 
sign so that the stroke of your brusli, in 
painting will pass parallel to the rib of 
the silk, and not across the woof of either 
silk or satin. Silk or satin is most easily 
painted with water colors, if you have not 
long experience in painting in oil. As to 
durability, a dress painted for the wed- 
ding garment of a Kevolutionary beauty 
was in a good state of preservation at the 
Centennial celebration of 1876 at New 
Haven. The dress was white silk; the 
design was painted in several shades of 
bine. There was no minute work; large, 
bold curves cut the white silk not covered 
by the blue arabesques, into graceful 
white forms. Paint, therefore, is a pre- 
servative. Silk or satin dresses, if painted 
[)roi)erly, may be bequeathed from one 
generation to another. It will then " })ay" 
to take some trouble to paint a good de- 
sign. Tracing.— If you are timid about 
painting at once oti tlie silk, use tracing 
])aper, because lead-pencil marks cannot 
he rubbed out easily. Go over the jmint 
line left by the tracing ]mper with thick 
colors, or paint, mixed with Chinese 
white. Transparent colors, laid on silk, 
will run into irregularly ugly shapes. 
The ])reparations used on silk to stiffen it 
and flll up the texture are various. The 
danger to be avoided is changing the 
shade of the silk or satin; therefore pre- 
pare the paint, not the silk. It is less of 
