( i-'s ) 

 T3Y degrees acquire a black complexion, yet the infides 'of their 

 bands and the foles of their feet are always white ; whence I con- 

 rlnded, that the Scales on their hands and feet are tranfparent. 



I know that there are many men among us who think (and I 

 have heard fome fay fo), that the blacknefs of the Negroes proceed 

 from no other caufe than their bodies being rubbed with fome 

 kind of oil. Tor, tay they, when born they are of a red colour 

 like our children. But in like manner as it is impolTible to 

 dye the wool or hair on the body of a flieep, horfe, or other 

 animal, fo that it ihall retain the colour, becaufe the hairs or wool 

 are continually falling off; fo it is impoffible to dye thofe Scales 

 that cover the Ikin, fo as to remain black, becaufe they very foon 

 drop off. And jjerhaps alfo the I'mall veffels which compofe the 

 Scales on the bodies of Negroes may affume a black colour, m here- 

 by the Scales will appear llill blacker, as v^e fee the veffels in Ibme 

 of the coats of the eye are quite black, and I doubt not are fo 

 iormed to preferv^e the blacknefs in the coats they compofe. 



Addition, by the Translator. 



Thr perafal of this effay calls to my recoUeftion a paffage in one of Mr. 

 Leeuwonhock's Letters to the Royal Society, not inferted in his works, 

 but printed in the Philofophical Tranfaftions ; in which, treating of the 

 callus on the hands and feet, Mr. Leeuwenhoek confirms what he has here 

 laid down, that a callus is only caufed by great numbers of Scales heaped 

 on each other. And he alfo obferves, that on wafhing and afterwards wip- 

 ing his hands, he was furprized at the great number of Scales which con- 

 tinually came away. Hence we may gather the reafon why, if the hands 

 are ftained with any thing (fuch as the juice of Avalnut peel) which will 

 not immediately wafh off, the (tain in a fliort time wears away : and why, 

 in a long feccffion from labour, the hands become fmooth and foft, foraf- 

 much as the difcoloured and concreted Scales fall off, and are replaced by 

 new ones ol the natural colour and confiflence. 



