quid glucose in 200 parts of distilled or rain
water and dissolve by heat over an alcohol lamp, stirring all the while.
Let the solution boil for an instant, and when the paste is homogeneous
let it cool down and then remove the skin formed on its surface and strain
it through a fine canvas. Now provide with three small sponges free from
gritty matters and cleaned in water, and nail by the four corners, one
over the other, felt size uppermost, as many sheets of paper as you wish
to size on a board somewhat smaller than the paper. This done, with one
of the sponges take a small quantity of the arrowroot and, brushing it
length-way and cross-way, spread the paste into an even layer, then, by
rubbing very lightly with the second sponge, efface the striae and smooth
the coating as well as possible. The third sponge serves to remove the
excess of paste when too much is at first spread on. From six to seven
sheets of paper, 18x22, can be sized with the quantity of arrowroot paste
above given.

Another, but not quite so effective a manner of sizing although sufficient
for the cyanotype, is the following, employed by Mr. Pizzighelli for the
paper used in the platinotypic process:

Ten parts of arrowroot are powdered in a mortar with a little water and
then mixed by small quantities to 800 parts of boiling water. After a few
minutes 200 parts of alcohol are added and the mixture filtered. The
paper is immersed for two or three minutes in the warm solution and hung
up to dry.

_Sizing, with Gelatine._--Dissolve at a temperature of about 140 deg. Fahr.
(60 deg. C.) 10 parts of good gelatine in 800 parts of water, then add 200
parts of alcohol and 3 parts of alum dissolved in a little water. Filter
and prepare the paper by immersion as above directed. The gelatinized
paper when dry should be prepared a second time and dried by hanging it up
in the opposite direction in order to obtain an even coating.

THE CYANOTYPE OR BLUE PROCESS.

_This process gives white impressions on a blue ground with diapositives
or drawings on transparent or semi-transparent materials, and blue
impressions on a white ground from negatives._ It is commonly known under
the names of "blue print process," "negative ferrotype process" and
"ferro-prussiate process."

The process is indeed exceedingly simple. A sheet of paper, impregnated
or sensitized, as it is termed, with a solution of ferric citrate and
ferricyanate is impressed unde