50 On the Steeping of Wool. 



and contains a substance with an agreeable smell, which 

 appears to be pertectlv analogoiis to that developed by am- 

 nionia, and with that discovered in it by the antienls. 



4. It ought to excite little i^urprise to see the quantity 

 of potash and of grease diminish or increase in sheep ac- 

 cordino: to tlieir state of disease or of health ; for a secretion 

 so complicated, requiring the utmost exertions of nature, 

 must invariably be intimately connected with the augmenta- 

 tion or diminution of the vital powers. But how is it pos- 

 sible to doubt that the grease has an immediate action on 

 the quality of the wool, when we see those two substances 

 proceed, if we may so express it, in harmony, from the 

 wild sheep of Greece to the most beautiful and the most 

 vigorous Merinos? It was probably to assist them to re- 

 cover this precious transpiiatlou, that the Romans, after 

 shearing, covered them with a mixture of tonic and oily 

 substances, which, according to Columella, preserved them 

 f'rom manv diseases, and contributed to render their wools 

 finer and lonwer. 



3. These vools constantly assume, in copper vessels, 

 solid colours, more or less deep, which, even at the lowest 

 degree of coloration, prevent theili from taking the first 

 shades of a tint. This effect is obviated by the use of tin- 

 vessels, the oxide of which cannot alter the whiteness of 

 the wool during steeping. 



6. All the experiments prove that the affinity for the 

 colouring matter varies in wools according to the healthy 

 or diseased state of the animal ; and that the wool of healthy 

 Merinos is always more highly coloured than not only Nos. 

 2 and 3, though the produce of the same flock, but even 

 than cill the carded wools- of France and Holland. They 

 show to what causes we oua'ht to ascribe the effects pro- 

 duced on wools the exterior characters of which are per- 

 fectly alike, and which, afier receiving the same prepara- 

 tions, assume, in the same vat, ditferent colours. 



7. The beautiful and very sohd blue colours obtahied 

 from wools in the grease, demonstrate, in a very positive 

 manner, the influence of that animal matter, which, if 

 transferred to other snhsliuices, niij^ht furnish the arts with 

 many highly useful applications. 



Of'servaiinns of the Aiithor. 



Since the reading of my memoir to the National Insti- 

 tute, f have received a coniplete proof of the facts to which 

 I Jiscribc the variations exhibited in 'Iv-'tug hv carded wools. 

 Havinj: attcvtaincd that the diffcreui cause's which exer-cised 



ail- 



