[ 3 ° ] 
*ng the denfity, vifeidity, and other qualities of this 
matter, or the manner in whicn it is difturbeclin 
the middle zone only, and not at the polar re- 
gions, and many fuch other queftions, I freely 
confefs, that they far furpafs my knowledge. 
To conclude ; as what hath now been laid may 
open a new field of inquiry into this fubjedt, lo a 
difeuffion of thefe curious points ma 7, fome time or 
other, fall to the fiiare of abler me n, whofe love 
of philofophy may induce them to purfue fo noble 
an invefligation. 
II. Ajlro* 
