[ *32 ] 
mined, but with little Satisfa&ion to the Learned : 
For which Reafon I have been more particular and 
explicit in delivering any Thoughts about it, as I have 
never known or heard of any fuch to have been de- 
livered by any others. As for what relates to the 
remote Caufes of the Colours of Negroes, it has been 
generally fuppofed ; although not univerfally believed, 
that the Power of the Sun in hot Countries is the 
principal, if not the only, Agent in producing this 
Elfed : Bur, as the Authors of this Opinion feem not to 
have underftood what Effed or Alteration is produced 
in the Make of the Skin, in order to render it black, 
fo they have not been able to fatisfy any one in this 
Point, and far lefs to vindicate their Opinion from 
many material Objections; for it would be very diffi- 
cult, if not impolTible, to fhew or prove, in what 
manner the foie Effcd of Blacknefs is occafioned by 
the Power of the Sun, but not fo difficult t6 fhew 
how it may make the Skin thicker or denier; which 
we fhall endeavour in the next place to do, by fhevv- 
ing in what Manner the Power of the Sun is able to 
caufe that Thicknefs and Denfity of Skin, which we 
have afligned as the immediate Caufe of its black or 
tawny Colour. But as this Subjed is much plainer, 
and more obvious, than the other, concerning the 
Make of the Skin, or the immediate Caufe by which 
its Blacknefs is occafioned, fo I fhall not dwell long 
upon it, but only give the principal Heads of thele 
Arguments, which ferve to prove this Propofition : 
Which Arguments are of two Sorts; viz. philofo- 
phical and hifforical ; the firft of which I (hall chiefly 
roach upon, being what are lcaft underftood, or, at 
leaft, hardly to be met with any-where die. 
The 
