^38 Method of giving to Cotton and Linen Thread 
proportion of a thirty-sixth part of boiled linseed oil, 
mixed with an alkaline solution of alumine, may be in- 
sufficient to excite spontaneous inflammation in skains of 
cotton heaped up after they have been dried. Those, 
therefore, who are induced, on account of the simplicity 
of the process, to employ a mixture of boiled linseed oil 
with an alkaline solution of alumine, must take the pre- 
caution to leave the skains extended and insulated on 
poles, until they are to be washed, previous to the opera- 
tion of dyeing, which, together with the brightening, com- 
pletely removes the excess of oil, and leaves only the 
portion saturated with oxygen $ so that no fears need af- 
terwards be entertained. 
Since the publication of my memoir, I have convinced 
myself that the simplest brightening of Adrianople red, 
by which the liveliest and most durable shades are ob- 
tained, consists merely in very long ebullition in bran 
water in a boiler furnished with a cover, having in the 
middle a pipe to suffer the vapours to escape, and pre- 
vent the bursting of the vessel ; care only must be taken 
to renew the water as often as it becomes red ; that is to 
say, two or three times at the commencement of the ebul- 
lition. Without this precaution the skains would contin- 
ually resume the fawn-coloured parts which the bran 
water removes, and would never acquire a bright colour. 
One may avoid all danger without lessening much the 
simplicity of my process, whether the skains be heaped 
up or not : nothing is necessary but to apply at two differ- 
ent times a stratum of olive oil, very much divided^ after 
they have been well lixiviated, washed, and dried. For 
this purpose, a ley is formed of carbonate of potash or so- 
dk, which indicates one degree, or a degree and a half, 
of the areometer for saltpetre. Some drops of olive oil 
are then dropped into it, to try whether the result will 
be a milky mixture, or whether the oil will ascend in its 
