344 
Lead, 
ing that prevents the evaporation of the moisture* Keep 
these pots in a warm place till they are full of crystals* 
Then draw the stopper, let the liquid part run out, and 
collect the crystals. The liquor that is drawn off will be 
thick, and too much loaded with lead. It must be di- 
luted with distilled vinegar, filtered, and again set in a 
warm place to evaporate, and crystallize. 
I believe the preceding process would be improved, by 
adding one sixth part of good distilled vinegar to the first 
clear liquor. T. C. 
The method of making sugar of lead as detailed by 
M. Pontier in the 37th voL of the Annales de Chirnie, 
p. 272, is in substance as follows. The vessels are casks, 
iron-hooped, with wooden cocks ; a copper still with a 
tin alonge (long tube adapted] or worm, and with a cock 
to let out the sediment ; stoneware jars to hold the vine- 
gar ; a cast-iron pot to melt the lead in ; stoneware jars 
also, to hold the vinegar and lead ; copper boilers tinned 
the same size of the still ; half a dozen or more wooden 
filters. 
Cast the lead in very thin sheets, as the plumbers do ; 
milled lead will not answer so well ; cut it in pieces in- 
discriminately ; put them in the vinegar distilled in your 
still, in the stoneware jars ; the vinegar should be strong ; 
do not close the jars, it is sufficient to cover them from 
dust ; change the oxyded lead two or three times a day, 
putting it in the place of the lead submerged ; boil the vi- 
negar with the white lead in it, in the tinned copper boil- 
ers, to finish the saturation ; (I think this can be done by 
putting the jars themselves with their contents in a bath 
of boiling water, T. C.) Filter the liquor ; evaporate to 
a pellicle ; (I think a sixth of distilled vinegar should be 
added, previous to evaporation, T. C.) dry the crystals 
in the shade. The residuum may be treated in the same 
way, but it does not give so clear crystals as z\t the first 
solution. 
