and Extension of ibe Merino Breed of Sheep. 34c 



of its deptli from the surface, a great quantity of dusf, eanli, and oit^cr matters, 

 either floating in the air, or lying on the ground, so as to give the Merino sheep 

 a very dark and dirty hue, corresponding chiefly with the colour of the soil. 

 As it happens that the finest fleeces have, usually, the greatest quantity of yolk, we 

 may, in unwashed sheep, living together, of the same age and at the same season, 

 form a tolerably accurate conclusion as to the fineness of the wool from the 

 degree of darkness on its surface ; which is also greatest on the finest parts of the 

 fleece, as on the neck, shoulders, and sides. Notwithstanding this superficial 

 darkness, the wool, when drawn asunder, has, nearer the skin, a brilliant silky 

 appearance, and, when scoured, is of the purest white. 



According to Lasteyrie, when the fleeces undergo the operation of washing for 

 sale, which is never performed on the sheep's back, but always after the wool is 

 sorted, they lose three-fifths of their weight. Bourgoing states this loss as beino- 

 usually two-thirds j but if we follow Lasteyrie, we find that five pounds, or eighty 

 ounces, become thirty-two ounces. Afterwards, in scouring by the clothier, a 

 further loss is sustained of about three, or three and a half, in twenty. Hence the 

 tViirty-two ounces are reduced to about twenty-six ounces and a half; which are 

 somewhat less than one-third of the original weight of the wool in the full yolk. 

 We may, therefore, state the average reduction in scouring the Merino wool of 

 Spain to perfect cleanness, to be at least two-thirds of the original weight of the 

 unwashed fleece. 



It is found, however, that the quantity of the yolk is different, not only in 

 different individuals, but in the same individual at different seasons. I do not 

 know that any very nice observations have been made on this subject ; but, as the 

 greater part of the yolk is easily miscible with water, it is obvious that a dry or 

 rainy season must make some variation in the quantity adhering to the wool, and 

 therefore in the eventual relative weight of the fleece. Whether the temperature 

 of the season has any influence on the production of the yolk, has not been hitherto 

 positively ascertained; but as I know that the fleeces of Lord Somerville's flock of 

 pure Merinos in England waste in scouring only one half, it is highly probable that 

 the proportion of yolk, in some degree, keeps pace with the heat of season or 

 climate. 



The French literati, alv/ays assiduous in applying the knowledge of nature to 

 the improvement of the arts, have not been idle on the subject of the yolk of wool. 

 VOL. V. Y y 



