488 Process for Dyeing JSTanJceen Colour . 
Sixth Operation . 
For every ten pounds of yarn make a ley from half a 
pound of pot or pearl ashes ; pour the clear ley into the 
boiling- pan ; add a sufficient quantity of water thereto that 
will cover the yarn about four inches ; light the fire, and 
enter the yarn, when the liquor is a little warm ; observe 
to keep it constantly under the liquor for two hours ; in- 
crease the heat regularly till it come to a scald ; then take 
the yarn out, wash it, and hang it to dry as in former 
operations. 
Seventh Operation . 
Make a sour liquor of oil of vitriol and w ater ; the de- 
gree of acidity may he a little less than the juice of le- 
mons ; lay the yarn in it for about an hour, then take it 
out, wash it very well and wring it ; give it a second wash- 
ing and wringing, and lay it on a board. 
N. B. This operation is to dissolve the metallic parti- 
cles, and remove the ferruginous matter that remains op 
the surface of the thread after the fifth operation. 
Eighth Operation . 
For every ten pounds of yarn dissolve one pound of 
best white soap in clear w ater, and add as much water to 
this liquor in your boiling-pan as will be sufficient to 
boil the yarn for two hours. When these liquors are 
well mixed light the fire, enter the yarn, and bring the 
liquor to boil in about an hour. Continue it boiling 
slowly an hour; take it out, wash it in clear water very 
well, and hang it to dry as in former operations : when 
dry it is ready for the weaver. 
N. B. It appears to me, from experiments that I have 
made, that less than four operations in the preparation 
of the yarn will not be sufficient to cleanse the pores 
