328 JVool in Relation to Science tvith Practice. 
effects on it of extremes of heat and cold ? This also is known, 
that the free secretion of yolk gives that most desirable quality in 
wool — density. In washing, wool loses about one-third* of its 
weight — at least, from one-third to half weight is deducted when> 
unwashed on the sheep's back, wool is bought— called wool-in- 
grease. When the wool is washed on the sheep's back, the soap 
of yolk is of course dissolved, and takes the salts along with it. 
M. Raspail estimates that the grease from French wool-washing 
would manure 370,000 acres. On the Continent, potash, which 
Dr. Voelcker somewhere puts at l^rZ. a pound, is in wool-washing 
and scouring operations carefully saved. The 1871 experience^ 
in the words of the Report, teaches us — 
In reference to our ' wool-scouring.' The best labour-saving machine we 
possess, up to a certain stage, is undoubtedly the machine of Mr. Petrie ; but 
we still need an improved apparatus, amplj' supplied with water for washing; 
off the suds, so as to rid the wool entirely from all unctuous matter before it 
is dried. 
" Let not our manufacturers, therefore, be taken unawares, if a couple of 
intelligent Continental wool-scourers, technically educated in chemistry, be 
presently found located within a few hundred yards of Mr. Petrie's works, 
introducing a new process of scouring altogether (as regards the chemicals 
used), yet in connection with Mr. Petrie's machines ; employing, after his 
sqiaeezing rollers, a ' washing-oif ' apparatus from the Continent, to complete 
this important operation. 
" It is also not improbable that instead of the usual alkali an ingredient 
will be used which can be reclaimed or distilled from the ' suds ' by a small 
still, so as to be used over and over again. This, too, in addition to the 
reclamation of grease from the sud." 
Mr. Fairley, the Yorkshire consulting chemist, who, from resi- 
dence at Leeds, is peculiarly qualified, has favoured me with the 
following practical note : — 
" The process of wool-washing, or rather scouring, in Leeds and similar A.\Sr 
tricts, is essentially a different process from that on the sheep-back of wool- 
washing by the wool-grower. The materials used for the 'scour' are lant 
(stale urine) and soap ; or lately, in place of the latter, soda-ash. This criTde 
but powerful alkali must be used with the greatest care, as the slightest 
excess seriously injures the wool. 'Ihe scouring is either done by hand or by the 
aid of the patent wool- scouring machine (Petrie's and other combined patents)i 
The wool-scouring is simply the first stage in the manufacture of wool into cloth. 
" In wool-washing, wherever practicable, the rain should be collected from 
the roofs of the farm-buildings, &c., and utilised. If the washing were per- 
formed with successive small quantities of water in vats, &c., through which 
the sheep could be passed successively, the minimum quantity of water would 
suffice ; and the vahiable potash now wasted, which forms, reckoned, as car- 
bonate from 7 to 8 per cent, of the raw wool. This potash is abstracted from 
the soil, and ought to be returned to it in a perfect system of wool-grovviug." t 
From the point of view of one of the most celebrated, ram- 
breeders in England, a professional farmer of great culture and 
* See page 331, note. See also Chemistry, page 326. It seems clear tl-.at the 
grower who sells wool-in-grease is unthriftj'. 
t See the late Mr. Torr's practice, page 34.'). 
