( m ) 
This Art of Printing coufifts in fix Articles • viz. 
- •* • V-Vf ••' • * ^ 4 * ' •’ ; " * t ' / f . -• 
I. To produce any Objed with three Colours, and 
three Plates. 
II. To make the Drawings on each of the three 
Plates, fo that they may exadly tally. 
III. To engrave the three Plates, fo as that they can* 
not fail to agree. 
IV. To engrave the three Plates in an uncommon 
Way, fo as that they may produce 3000 and more 
good Prints. 
V. To find the three true primitive material Co- 
lours ■, and to prepare them, fo as that they may be 
imprimable, durable, and beautiful. 
VI. To print the three Plates, fo as that they may 
agree perfectly in the Imprellion. 
The jirjt of which is the moft confiderable, com- 
prehending the 'theoretical Part of the Invention ; 
and the other five are fubfervient to bring it into me- 
chanical Pradice, and of fuch Importance, that if any 
one of them be wanting, nothing can be executed 
with Succefs or Exactnefs. Sometimes more than the 
three Plates may be employ’d •, viz. when Beauty, 
Cheapnefs, and Expedition require it. 
The Obfervation of the compounded Colours re- 
flected from two Pieces of Silk, of different Colours, 
placed near together, firft gave him the Thought of 
what the EffeCt of weaving Threads of different Colours 
would be, when all the Threads were fo fine, as not to 
be diftinguilhed at a fmall Diftance one from another. 
O * - By 
