of Sutflances in Spirit of Wine . 157 
inconvenience did not happen, or not in fo great a degree, 
though then lefs foap was of courfe obtained. 
As diachylum, though with a greater proportion of litharge, 
and boiled longer than that I had from the Hall, ftill con- 
tained oil not fufficiently faturated, I made the metallic foap 
in another way. To a folution of fugar of lead in water I 
added a folution of alkaline foap in the fame liquid. A double 
decompofition took place, the oil uniting with the calx of lead, 
the alkali with the acid of fait. Ufing this metallic foap in- 
ftead of the other, I obtained an alkaline foap harder and 
more perfefl than in the preceding procefs ; but ftili found that 
part of the oil remained with the calx of lead in the refiduum, 
and adhered fo firmly, that repeated quantities of fea fait and 
fpirit of wine did not wholly feparate it. 
As I have given this procefs more with a philofophical view 
than any other, I have been thus particular in my account of 
it, to (hew that however eligible it may appear at firft view, it 
will not anfwer for making foap for common fale. The alkali ■ 
indeed is procured much cheaper than from barilla, as the lead 
may be revived and re-calcined into litharge. But the whole 
of the oil or fat cannot eafily be converted into foap, though 
in order the better to effe£t it, I have mixed fand with tho> 
diachylum: and as the oil and litharge muft, in the large 
way, be united by boiling, a confiderable part of the former 
will not be fufficiently faturated. Fuel muft be ufed, not only 
for forming the metallic foap, but likewife for decompofing 
that foap, and then diftiHing off the fpirit, which will alfo 
require additional time and labour. The quantity of fpirit 
of wine loft, though the procefs (fo far as that liquid is con- 
cerned) be performed in a ftill, will alone nearly counter- 
balance the faving in refpefl to alkali. And in the procefs itfelf 
there 
