Leach 
231 
would be established to a considerable extent and at no 
expence. When I suggested this to a vinegar manufac- 
turer in Gloucestershire, whose works I examined, he 
promised to give it immediate trial ; but I left the country 
without an opportunity of knowing whether he did so or 
not. 
I have already mentioned, that the process of making 
carbonat of lead, by precipitating the nitric or acetic salts 
of lead, by carbonat of potash, although the article be very 
white, is too dear for a manufacture in the large way. 
The carbonat of lead thus made, on an average of the ex- 
periments of Bergman, Berthollett, Klaproth, and Che- 
venix, consists of 84,13 lead, and 15,87 acid. But the 
carbonat of lead can be made by treating the suiphat and 
muriat of lead, which, form the refuse in my mode of 
bleaching, with carbonat of potash ; a process which be- 
longs to, and is part of the process, I claim to myself; 
and which, until I procure a patent for it, any one is web 
come to use. 
I come now to the neatest, most scientific, and most 
economical method of making white lead, founded upon 
Lord Dundonald ? s patent of decomposing the muriat of 
potash, by litharge or any oxyd of lead. To make this 
perfectly intelligible, I must go back to the history of 
Turner's mineral yellow ; the common, heavy, hard, fus- 
ed, patent yellow of the colour shops, and in common use 
with the coach-makers and chair- makers. Turner took 
out a patent for making this colour about eight and twen- 
ty years ago, which being contested, was set aside, owing 
to the gross ignorance on the subject, of the Court of 
King’s bench and the bar. 
Turner, by a mill-stone rolling vertically in a circular 
trough, triturated for 12 hours together in the form of a 
paste, two parts by weight of common salt, and one part 
of litharge. He would have done better by three parts of 
