4 © mineral q g i d a l 
becaufe a part of the reduced tin was again 
calcined, and mixed with the fcoria j for 
this reafon I repeated the laft experiment, 
but with this difference, that I kept the 
mixture only half an hour in the fire, and 
the refult fhewed, that I had approached 
the proper time for now I obtained 
304 grains of pure filver-coloured tin glo¬ 
bules, upon which the loadflone had no 
effed. 
(d) Under the fame circumftances I 
made two other afiays, one with the tin ore 
from Schlackenwalde in Bohemia, and the 
other with the pure cryftallized tin-ftone 
from Mengarnin Cornwall. The powdered 
tin ore from Shclackenwaldegave 16 grains 
of globules of tin of an iron-grey colour, 
and very attradable by the magnet. 
e Afterwards I tried the redudion on¬ 
ly by the addition of phlogifton without 
any flux. I mixed 1 dram of wood-tin 
with an equal weight of colophony in a 
crucible covered with powdered charcoal, 
and let it remain half an hour in a melt¬ 
ing 
