[ <574 3 
The Method in which it is made at Liege, where 
I firft faw it, and made fome myfelf, is as follows : 
Take j of uniduous Clay, (fuch as Brewers ufe to 
bong their Veflels, in it there mud be neither Sand, 
Gravel, or Stone) 
And -f of Coal-dud : Mix, and make them incor- 
porate well together; cad them into round Balls, or 
Bricks ; and you may put them on a Coal-fire, and 
they will burn direttly. But if they are made in 
Summer-time, and laid to dry for Ufe in Winter, 
they will light fooner. 
Thus you have an hot, clean, lading Fire, not at 
all offenfive to the Smell. 
The Dud is there theRefufe of the Mine, and may 
be here of the Coal-merchant’s Yard, fo that this Fuel 
comes exceeding cheap. 
Nor is it necefiary to put fo much Coal-dud; for 
fome Clay (particularly what I ufe myfelf in the 
Country) will do, if mixed -y Clay, J Coal-dud ; and 
the true Proportion of the Mixture mud be found 
by Experience ; but it is always better to put in too 
much than too little Coal-dud at fird, becaufe Men 
are too apt to be difcouraged in making Experiments* 
This Fuel is not only to be had at an eafier Price, 
but it is likewife more durable. 
How far it may be ufeful in Glafs-houfes, Brew- 
houfes, Salt-works, &c. I mud leave to the Confider- 
ation of the feveral Perfons concerned in them. 
I have heard, that at Liege they burn both Lime 
and Brick with it; but, as I never faw it done, I can- 
not affirm it. 
IV. A 
