The shorter combing wools are in general used for hose, and are softer than the long combing wools. Short wool is employed in the cloth manufacture, and is, on that account, frequently called clothing wool. It should approach in colour as much as possible to white, as a clear white ground is required for all cloths that are to be dyed bright colours, as well as for those dressed white: grey or black hairs injure the fleece very much, even though few and minute, as they give rise to reddish spots where the cloth is stoved. Herefordshire sheep are entirely free from this defect, and are, therefore, reckoned particularly valuable for clothing purposes. (35.) _Alterations induced by Crossing._--The breed exercises considerable influence on the wool, some sheep, as the merinos, being distinguished for the softness and beauty of the fleece; while others, as some of our small northern varieties, are famed for the very opposite characteristics. According to the opinion on the continent, any race of ewes, however coarse and long in the fleece, will, on the fourth cross of the merino ram, give progeny with short wool equal to the Spanish. The truth of this proposition is however doubted, in a communication to the Board of Agriculture, by Dr Parry of Bath; but it is certain, he adds, that one cross more will in most cases effect the desired purpose. "If we suppose," he says, "the result of the admixture of the blood of the merino ram to be always in an exact arithmetical proportion, and state the native blood in the ewe as 64, then the first cross would give 32/64 of the merino, the second 48/64, the third 56/64, the fourth 60/64, the fifth 62/64, and so on. In other words, the first cross would leave 32 parts in 64, or half of the English quality; the second 16 parts, or one-fourth; the third 8 parts, or one-eighth; the fourth four parts, or one-sixteenth; the fifth 2 parts or one-thirty-second; the sixth 1 part, or one-sixty-fourth; and so on. Now, if the filament of the Wiltshire, or any other coarse wool, be in diameter double that of the Ryeland, it is obvious that, according to the above statement, it would require exactly one cross more to bring the hybrid wool of the former to the same fineness as that of the latter. This, I believe, very exactly corresponds with the fact. The difference between one-eighth and one-sixteenth is very considerable, and must certainly be easily perceived, both by a good microscope, and in the cloth which is manufactured from such wool. In the latter method, it certainly has been perceived; but I have had hitherto no opportunity of trying the difference by the former. The fifth cross, as I have before observed, brings the merino-Wilts wool to the same standard as the merino-Ryeland."