{ 6 ] 5 ) 
are fufficiently fcaled, to fcour them with Sand, and 
when there remains no more black Spots upon their 
Surface, to throw them into Water to prevent their 
rufting again, and leave them in it till the Inflant you 
would tin them, or in the Term of Art, blanch them. 
This he obferves is the very Objed of the whole Art, 
and is kept as much a Secret by the j B lancher^ as the a- 
cid eroding Menftruum is by the Scaler : But the Man- 
ner of doing it is thus. They flux the Tin in a large 
iron Crucible, which has the Figure of a broken Pyra- 
mid with four Faces, of which the two oppofite ones 
arelefs than the two others. This Crucible they heat 
only from below, its upper Border being luted in the 
Furnace quite round. The Crucible is always deeper 
than the Plates which are to be tinned are long, which 
they always put in downright, and the Tin ought to 
Iwim over them. For this Purpofe Artificers of differ- 
ent. Trades prepare the Plates in different Manners, 
which are all exceptionable : But the Germans he per- 
ceived made ufe of no Preparation whatfoever, exceot 
putting the fcoured Plates into clean Water, as juft 
remarked j but when the Tin is melted in the Crucible, 
they cover it with a Layer of a Sort of Suet, an Inch 
or two thick, through which the Plate mult pafs before 
it comes to the Tin : The fir ft Ufe of which is to 
keep the Tin from burning, and if any Part fhould take 
r ire, as the Suet will foon moifteoit, to reduce it to its 
natural State again, d his Suet is compounded, as the 
Blanchers fay, and is of a black Colour, which the Au- 
thor thought might be given it with Soot or the Smoak 
of a Chimney, only to fpread a Myftery over their Work ; 
but he found it true fo far, that common unprepared Suer 
was not fufficient : For after feveral Attempts" there 
^ ^ P P P 2. -was 
