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Ouill, drawn fmaller than the natural fize. AtABG, are repie- 

 il-ntcd thofe veirels which compole the external part of the Quill, and 

 lie in it longitudinally ; BCFG, are thofe which take their courfa 

 round about it ; CDEF, are tlie veflds, which, like the firll'men- 

 tioned ones, are placed the length way of the Ouill. 



From thel'e obfcrvations, I difcovered the reafon, why fome OuilJs 

 when they are fplit lengtliwife, in that j)art where tliey are hardefl, 

 form a kind of indented or jagged part in the filfure ;* namely, be- 

 caufe thofe velTels, whole courfe is round the Ouill, are not all 

 broken in an even ftraight line ; efpecially, as I laid before, where the 

 Quill is liardefl : and where thefe vedels are heaped together in greater 

 quantities than in other parts. Therefore, to prevent this accident, 

 wlien the Quill is fo very hard, it is neceirary to fcrajie it a little 

 with the pen knife, by which means, in the fplitting, it will be llraiglit 

 and even. 



I have frequently, by tlie microfcope, contemplated that part of thefe 

 Quills which is called the feather, and alfo the feathers of fmall birds; 

 and always viewed them with admiration ; not only on account of 

 the multitude of parts to be feen in them, but alfo, by reafon of tire 

 great numbers, and extreme minutenefs of the vellels, of which, not 

 only the whole featlier, but every little part of it is compofed. 



To exhibit to the view, the great numbers of vefiels of which tlie 

 feather conlUls, I placed a fmall piece of one before a microfcope, 

 and a drawing of it is given ^tfig- 2, LMNOPO. 



In the preceding /^. 1, DHIKE exhibits part of the feather of 

 the common writing Ouill, fmaller, as before obferved, than tlie 

 natural fize. At K, is reprefented a fmall part of the feather, a piece 

 of which, i'een by the microfcope, is fhewn ^tfg. 2, for, if thewiiolje 



* This mod commonly happens in thof: Q^iills which have not been, what is' called 

 clarified, or when the Qviill is fplit near the feather; this jagged fhaps of the fplit is w^Ui 

 known to fchool boys, and is denominated by them, cats teeth. 



