MttchelL 279 
rent Climates." It was deligncd as a fo- 
lution of the prize problem from the Aca- 
demy of Bourdeaux ; but was publiihed in 
the Phihfophical Tra72faBionSy Vol. xliii. 
pp. 102 — 150. 
The queftion concerning the caufe of the 
black colour of the Ikin in Negroes, has 
exercifed the pens of many philofophers and 
anatomifcs. What has perplexed the quef- 
tion the more is, that thefe ingenious wri- 
ters (among whom are principally Malpighi, 
Boyle y WinfloWy Meckel y and Barrere) have 
differed about matters of fail that fhould 
feem to be cognizable by the fenfes. 
It would be improper in this work to 
purfue the learned author through all his 
ingenious details and curious fchoUa on this 
fubjed: ; it muft be fufficient to obferve, 
that, on the Newtonian dodrine of the caufes 
of colours, he deduces the colour of the 
fkin of Negroes from the ftrudure, after 
eftablifhing certain propofitions : i. That 
the colour of White People proceeds from 
the colour which the epidermis "tranfmit$. 
2. That the denfity of the ikins of Negroes 
allows of no tranfmiffion of colour. 3. The 
T 4 part 
