Sfffc Researches respecting the 
I have tried also a mixture of equal parts of lime and 
argil, to which I added one part of silex, and likewise 
without silex ; but this mixture did not supply the place 
of talcky sand. This sand is not in general found in 
grains ; it exhibits itself most commonly under the form of 
a stone, such as free-stone; but some of it is found also 
in grains. 
We should be much deceived in making white enamel 
were we to employ the oxyds of tin and lead separately, 
as I have read in all the authors I could find who 
treat on the art of pottery. None of them say what 
they ought respecting enamel, nor even respecting the 
composition or nature of the earth proper for bearing an 
enamel. 
It is essential that the lead and tin for making the 
oxyd employed to produce white enamel, should be fused 
and mixed together before they are calcined ; and if you 
wish that the enamel should immediately acquire its full 
whiteness, it will be necessary that the calcination should 
be complete. 
Bismuth might perhaps be employed as a substitute for 
the lead, and it is not improbable that it would give a 
good effect. Bismuth also might be mixed with the lead 
in the following maimer ; namely, one part of lead, one of 
bismuth, and one of tin : or other proportions might be 
employed ; but I have not tried any others. As the oxyd 
of bismuth, however, is exceedingly fusible, I think it 
might be admitted, with great advantage, into certain 
iluxes. I have not tried what might be produced by the 
white calx of zinc, nor by that of tin, made by dissolving 
it in the nitric acid or by detonation with nitre. A mix™ 
lure of lead and tin, detonated with nitre, would be use- 
ful. Though the white calx of regulus of antimony made 
by nitre, and well washed, (diaphoretic antimony,) pro- 
duces a very beautiful white enamel when fused with 
