SCIENCE 
IS 
KNOWLEDGE. 
KNOWLEDGE 
IS 
POWER, 
A PRACTICAL JOURNAL OF 
HOME ARTS. 
Vol. VI. 
NEW YORK, DECEMBER, 1883. 
No. 12. 
Overglaze Painting on Porcelain— IV. 
BY AURELIO -DE VEGA. 
EDIUMS.— 30. 
Tiiese are re- 
quisites, and 
upon tlie kind 
used and upon 
their quality 
depends, to an 
extent greater 
than is gener- 
ally supposed, 
the appear- 
ance of the 
finished work. 
The mediums 
are, as their other general name of vehi- 
cles indicates, the carriers of the paint, 
the means by which it may be spread. 
31. Unsatisfactory Mediums —^q\qvb\ 
things have been tried from time to time 
as vehicles, in fact, pretty well every- 
thing that, having some substance of its 
own and being adapted to be smoothly 
spread, would hold the pigment in sus- 
pension. Thus we find among those not 
unfavorably mentioned occasionally, gly- 
cerine, syrup of the "golden" variety, 
and gum. The thinning agent for use 
with these is water. Now, glycerine is a 
very good thing in its place, as, for in^ 
stance, when used in moderation foi 
keeping water color moist, or for chapped 
hands, bat it is certainly not in its proper 
place when on the china painter's palette. 
Water, when mixed with glycerine or 
syrup, evai)orates very slowly, and the 
painting would be constantly liable to be 
smudged. Moreover, the saccharine un- 
crystallizable portion of the medium 
would be very likely to boil up in the 
muffle. Gum, when dry, will, under heat, 
pulverize and mix with the paint, produc- 
ing an unsatisfactory appearance. I re- 
commend, therefore, that all such medi- 
ums as these be avoided. 
32. Satisfactory Mediums— D\q medi- 
ums which are in general use and give 
every satisfaction, are of two kinds—a 
spirit and an oil ; the latter being the 
vehicle proper, the former the thinning 
agent to render practicable the spreading 
of the mixed oil and paint in a coat of any 
desired depth or thickness. The spirit 
and the oil are both either of turpentine 
or of tar— spirit and oil of turpentine be- 
