234 Supplement to Dr. Parry's E^ia;* 



The same observations suggest many other important enquiries, which will require 

 various new experinfients, but of which, as my leisure from more important avo- 

 cations may chance to permit, I shall not lose sight. 



We are told by Daubenton, that there is no wool, however coarse, which has not 

 in it some filaments, of which the diameter does not exceed the 560th part of a line 

 of the foot-royal of France.* Now the French line being the 1 2th part of an inch, 

 and the French foot-royal being to the English as 1068 to iooo,t the diameter of 

 such filaments will be -g-^V? of a French inch, or --jVt of a^i F.nglish inch. So also, 

 according to the same author, the finest wool has some'filaments, of which the coarse- 

 ness reaches -\- of a line, or — to- °f ^ French inch, corresponding, as before, to 

 ■~j-j of an inch English; and this latter diameter he gives as the lowest size of the 

 finest wool.;]; 



Now out of upwards of 1 100 measurements which I have made, the smallest dia- 

 meter which I have ever fuund was at the inner end of a filament of my Merino- 

 Ryeland ram No. 6, the projected image of which, magnified 1250 times, was 

 equal to -i-|f- of an inch, making the real diameter of that part of the filament only 

 ^.J-5-5. of an inch : and the smallest mean of 10 measurements was only ytt-o of an 

 inch, as specified in the table, in the inner end of the filaments in my ewe No. 5. 



On the other hand, in each of the finest specimens of wool which I have examined, 

 which are the 6 first in the table, there were one or more filaments from -j-q— to 

 •^^ of an inch in diameter ; and instead of admitting -j-rVrof ^n inch as the lowest 

 term of superfine wool, out of more than 1100 measurements I have found only 42 

 filaments, of which any part reached that degree of minuteness. 



According to Mr. Luccock, a sample of moderately fine Spanish wool reached 

 ^3-5. of an inch j and the average diameter of the choice locks of native English 



» Avec ce micrometre applique au microscope — j'ai vu qu'il n'y avolt point de laines, meme 

 des plus glosses, ou il n'y eut des filamens tres fins, dont la grosseur n'est que la cinq-cent-soix- 

 antieme partic de la lignc du pied de roi. Inslruclion pour les Bergers, p. 339. 



■\ Throughout this work I have assumed this proportion of the French to the English measure 

 from Greaves, who took it from the French standard preserved in the Chatelet. If, according to 

 Hutton's Dictionary, article Measure, we allow it to be only as 1065I to 1000, the difference, in 

 the instances in which I have aj)plicd the rule, is of no consequence, and easily calculable by the 

 reader. 



X Les laines les plus fines ont quclques filamens, dont Ic grosseur va jusqu' a la ccnt-quaran- 

 tieme partie d'une ligne. J'ai fixe a ce point le premier lermc dc la hiinc supeifine. Instruction 

 pour les Bergers, p. 339. 



