GEOGRAPHY. 293 



t)F Vefuvius, jEtna, Stromboli, of Hockla and 

 Krabla in Iceland, of their eruptions, their lava, 

 and their effects. It treats likewife of the defarts 

 of thofe uninhabited countries in northern Afia, 

 which arc called Steps -, of the natural produc- 

 tions of each climate and country, and of all 

 that relates to the philofophical ftate of our 

 globe. It then extends its inquiries to the in- 

 habitants of the earth, and endeavours to deter- 

 mine their number, and the principal alterations 

 that attend it, by the aid of political arithmetic: 

 and from thence it concludes, that this earth is 

 capable of maintaining 3000 millions of inhabi- 

 tants, but that there are not in fact more than 

 1000 millions exiibng. It generally allows thir- 

 ty-three years to each generation : and on that 

 luppofition there are 1000 millions of mankind 

 that are born and die within the fpace of thirty - 

 three years , more than thirty millions each year, 

 #2000 each day, 3400 each hour, 60 each mi- 

 nute, and one each moment. The number of 

 the two fexes is nearly equal, which proves that 

 polygamy cannot contribute to the increale of 

 the human race, and that the celibacy of the 

 clergy, the monks and nuns, is an unnatural and 

 horrid practice. Mankind are diitinguifhed 

 into white, black and inulattoes. 



VIII. That part of geography which is called 

 ograpby^ or more properly Jlydrology* ex- 

 amines, in an hiltorical manner, the nature 

 prop the iburccs from wlu-iu < 



pro 



