hite wax 25 parts
Mastic 3 parts
Turpentine 100 parts

Dissolve by heat, first the mastic, then the wax, and keep for use in a
large mouthed vial.

MATT VARNISH.
Sandarac 6 parts
Mastic 6 parts
Lavender oil. 0.5 parts
Ether 100 parts

When dissolved, add 30 parts of benzine. The opacity of the film varies
with the quantity of benzine added; by excess the varnish dries
transparent.

WATER COLORS WHICH RESIST THE ACTION OF LIGHT.
Red. Indian red. Light red.
Orange. Mars yellow.
Blue. Cobalt blue. French blue. Smalt. New blue.
Brown. Raw umber. Burnt
sienna.
Green Terre verte.
Yellow. Cadmium Yellow Roman ochre.
yellow. ochre.

APPENDIX.

Although we intended to only describe the printing processes without the
use of silver salts, we thought it would be well to complete this work by
giving the most practical and interesting processes ever published to
obtain permanent photographs; as they may give rise in the hand of
experimenters to useful applications.

From time to time processes are published under "queer" names, which are
based on the well known actions of reagents on the ferric salts reduced by
light. They are derived from those described in the following pages.

We call specially the attention of the reader to the process of Poitevin,
by which one can experiment with every ferric salts, citrate, lactate,
oxalate, tartrate, benzoate, etc., by simply exciting with the
corresponding acid. Observe that to obtain good results the paper should
be strongly sized; it is a sine qua non, although not recommended by
Poitevin.

C.J. BURNETT'S PROCESS(1857).

"A capital process for many purposes," says Mr. Burnett, "is to float or
_steep_ the paper in a mixed solution of bichromate of potash and sulphate
of copper, as for Hunt's chromotype process.(36) I have mixed gelatine, or
occasionally grape sugar, or both with the solution;(37) but instead of
developing it with nitrate of silver, as in chromotype, wash out the salt
unaltered by light, and develop by floating on a solution of ferrocyanate
of potassium. The purple red color of the copper salt which now forms the
picture may be modified or changed in many ways,(38) viz., by soaking the
picture, after the ferrocyanate of potassium has been washed out of the
lights, in a s