1 74 Intelligence and Miscellanies. 



hibit after this operation. Some pigments present a chem- 

 ical combination with the oil, while others can be suspedded 

 in it only by considerable labor, and soon separate when left 

 at rest. These differences can be rendered of triflinji impor- 

 tance, by employing such a substance as will retain those com- 

 pounds which possess no attraction for the oil, in a state of 

 uniform supension and whose action will be in some respects 

 analogous to that of the gum used in inks and water colors. 

 The property which the hydrate or carbonate of alumma 

 possesses, of mixing freely with oil so as to form a transpar- 

 ent, consistent, and almost colorless compound, admirably 

 fits it for this purpose. At the request of Mr. Rembrandt 

 Peale, I prepared some pigments by mixing them with alu- 

 mina while moist. When ground with oil, he found them 

 to possess all the most valuable properties of the best col- 

 ors. The tendency to separate from the oil and the disagree- 

 able property, which some colors possess, of becoming more 

 fluid when an attempt to preserve them is made by immer- 

 sing the pallet in water disappear, after they have been 

 ground with a small portion of alumina. The artist has it 

 in his power thus, to increase or diminish the fluidity of his 

 paints and to render them uniform. Some pigments become 

 valuable as glazing colors, as the Prussiate of copper, (Hatch- 

 ette's Brown.) Vermillion and Naples Yellow, acquire new- 

 properties. 



For printing from blocks, as in the manufacture of orna- 

 mental floor-cloths, it is often desirable to increase the fluid- 

 ity of the paint, so as to prevent the dropping of small 

 thread-like parts on the work, without causing it to spread. 

 This may be accomphshed, by adding a small quantity of 

 whiting to the pigment while grinding ; the artisan can then 

 load his blocks with paint and consequently give a thick coat- 

 ing to the print. 



A. A. Hayes, Roxhury Laboratory. 



6. On a fine scarlet pigment for the pallet. — While prose- 

 cuting some experiments on the pigments employed by art- 

 ists, I prepared a quantity of the biiodide of mercury and 

 gave it to Mr. R. Peale, requesting him to make some ex- 

 periments on its working properties and permanency. This 

 distinguished artist, obligingly commenced them, but they 

 were not finished, at the time he left this country. He found 

 that it readily mixed with oil ; combined with other colors 



