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the difference of fize varying with the difference of 

 temperature in all proportions, the fize of the fila- 

 ment continuing the fame only where the animal has 

 been kept in an equal temperature of heat during 

 the whole period of its growth. 



Hairs, on the contrary, feem to have always a 

 determinate fliape and relative proportions, under 

 whatever circumflances they fliall have been pro- 

 duced — one fpecies of hairs being of one (liape and 

 proportion, and another kind of another fhape. In 

 general, (and with no exception that I know of) 

 the body-hairs of animals are thickeft at the root, 

 and taper fenfibly towards the point, which is diredly 

 the reverfc with all wool of grown flicep in this 

 country. 



By thcfe two criteria, w^ool may be, in general, 

 difl-inguilhed from hair, where they are entirely un- 

 compounded, without difficulty. But as all the dif- 

 ferent varieties of flieep breed readily with each 

 other, and produce a mongrel race, in which the 

 difcriminative qualities of the parents are blended 

 together, it neceffarily follows, that where the mon- 

 grel breed is produced between a wool and a hair- 

 bearing race, it will afford a fleece that can neither 

 be diflinftly charafterifed as hair nor as wool, but 

 will participate of. the qualities of both. If this 

 mongrel fhall mix again with a wool-bearing race, 

 the fleece of the defcendant will approach nearer to 

 wool J if with a hair-bearing race, nearer to hair; 



and 



