f6S On the Green Colour for Taint'mg, ^c. 



julus of a green colour, cxcccdinglv intense, the weight of 

 which aiiioiuUed to no more than 06-3. 



The neck of th^ retort was sUghtly hncd with some small 

 portions of green oxide, and of a substance of a darker red 

 than that of chromate of mercury, hut which I svippose to 

 be, with some niodifscaiions, the same combination. 



I have not yet determined the wei2;ht of the oxvjren gas^, 

 but it niav be casilv seen that the defect 03' 7 minus the 

 quantity of oxygen which constitutes the oxide of mercury 

 at a minimum, expresses nearly the dilfcrcncc which exists 

 between the state of oxidation and that of the acidity of 

 chrome. 



This oxide alone, bv its. mixture with the carbonate of 

 lead (white lead), furnishes durable and varied lints ; but 

 it is no doubt more advantageous to employ it in the state 

 of combinafion with an earth ; for it appears certain that 

 in this circumstance the colours of the metallic oxides ac- 

 quire uiore' brilliancy and durability, as we find to be the 

 case in ultramarine, smalt, sienna, earth, ikc. 



The ^reen of chrome, besides the advantage of being use- 

 ful in painting- in oil and distemper, may, with the ne- 

 cessary quantitv of flux, be applied immediately on porce- 

 lain, and can endure the greatest heat without alteration. It 

 may be employed for painting on class, in enamel, and for 

 cpnimunicating to crystal the colour of the most beautiful 

 emerald. It may be used in general for ornamenting pot- 

 tery of all kinds. I have found by experiment that it may 

 be prepared at such a price as to be within the reach of all 

 manufacturers. The difl'crcnt essays I had had the lionour 

 to submit to adnii nisi rati on seem to me suf^clent to induce 

 me to hclieve that this colour will one day furnish a great 

 resource to our maitu factories. 



I propose to make known other observations proper to 

 enlarge, tlie history of chrome, as well as of some prepara- 

 tions, which, perhaps, as well as artificial chron)atc of lead, 

 already mtroduced mtcv paiiUing, may become interesting 

 lo the arts; but I wish to have leisure to present in order 

 the notes I may be enabled to make on this substance, of 

 more importance to be. studied, as the territory of France 

 sccius to furnish it in abundance. 



J{ps7/fi of tito Analysis of the Chromate of JShrcwtf. 

 Oxide of rrjirome - - - - 12*6 



Oxide of mercury - _ - - S3' 

 Difference between the state of oxidation 



and that of the acidity of chrome - 4-4 



10i)-d 

 XLVII. fl.v 



