WOOL QUALITY MEASUREMENT

WOOL:

         Colour: white ; a small percentage of breeds give fawn, brown, or black fibres. Handle: varies from extremely soft (wools with fibres as fine as xashmere) to extremely harsh (wools of long staple, out standing scales, and diameter as thick as medium mohair) . Diameter: average qualities are from 40 to 60 microns thick, according to staple and breed.  Merinos and fine botany wools are from 15 to 40 microns. ( See Chapter IV, on " wool quality ") Cross section : the mean retio of long to short axis is 1.25 or more . Surface : no longitudinal crinkles are visible. Seales: prominent, stand out well form the fibre, averaging 10-12 scales per 100 microns length of fibre, but 7-9 per 100 microns for very fine wools. A scale length of 17-18.5 microns coupled with a ratio of diameter (scale length)3 ,which is less than 140, points to wool rather than to mohair, The scales stand away from the fibre and are not thrown out of focus by a small  movement of the microscope fine adjustment, In finr merino the scales are somewhat over lapping and cylindrical, one scale going all round the fibre (coronal).  In fine qualities the edges of the scales are smooth and straigth, In coarser wools the edges are serrated and wavy are long, and do not go round the fibres, The scales are sometimes free from the body of the fibre for one third or more of their length .  :Lustre :wools have regular, even scales, fitting closely to the fibre . Low lustre wools have rough sxales, irregules fitting loosely inkicate soft and supple wools; if rhey fit closely the fibre is stiff . Medulla : usually absent, except in coares wools . Beard bairs:
Mostly absent, due to sorting of the fleece into qualities.
Kemps: if the scales coalesce during growth they form a continuous sheath which is impervious to water and dye solution: this sheath is a rigid epithelium which makes the fibre stiff, prevent good spin-ning into yarn, and produces weak yarn.
Kemps are found mostly on the neck and legs of the fleece, and in deseased sheep.

                                                   Casein 
Boil the fabric in water . cool ,to 5c.c.all 1-2 drops of conc.
H2SO, and I drop of 3 % formaldehyde; pour gently on to 2 c.c. of conc.
H2SO4 containing I dorop of 10 % ferric chloride, without mixing :
Violume indicates casein, provided it is present in a form sufficiently soluble for extraction.