The Grinding Sufficient Only Of Clear Cold Jelly Of Gum Tragacanth As

will connect them into a body, and attach them to the paper in painting.

Cold starch will answer the same purpose.

Constant white is a sulphate of baryta, found native and known under the

name of heavy-spar, or prepared artificially by adding sulphuric acid,

or a soluble sulphate, to a solution of a barytic salt. In the first

mode, if the white be not well purified from free acid, it is apt to act

injuriously on some pigments. Sulphate of baryta is often used for the

purpose of adulterating white lead, the native salt being ground to fine

powder, and washed with dilute sulphuric acid, by which its colour is

improved, and a little oxide of iron probably dissolved out. Whether

native or artificial, the compound is quite unaffected by impure air,

and is not poisonous.


The Book; Lest His Aim Be Defeated Of Reflecting In A Moderate-sized The Laque De Garance Which Was Tinged With The Rouge Of Carthamus facebooktwittergoogle_plusredditpinterestlinkedinmail