INFLUENCE ON RECENT SCIENCE 97 



crusts on its surface, similar to sun-spots, a phe- 

 nomenon then recently made known by the telescope. 

 Sun-spots, because of the superior agitation of solar 

 matter, are broken up and disappear, but the earth- 

 spots formed more rapidly than they dissipated, finally 

 covering its surface with a thick crust of many layers, 

 composed of what he called matter of the third kind. 

 This crust diminished the motion of the terrestrial 

 vortex and finally destroyed it altogether, so that the 

 earth with its atmosphere and its obscure bodies de- 

 scended toward the sun to the place it now occupies. 



With the earth in its proper position and with the 

 beginnings of diversity in its composition, Descartes 

 was free to employ the remainder of his treatise to the 

 description of the character of each aggregation of 

 elementary matter necessary to form the various 

 chemical substances; the proportions and velocities of 

 the three kinds of matter to produce forces, such as 

 cohesion, weight, etc., and the different geo-physical 

 phenomena, such as winds, rain, and earthquakes. It 

 is amazing how much he passes before our eyes, and 

 how ingeniously he links his ideas, giving to them the 

 appearance of the greatest plausibility. 



There is little profit in discussing these at length, 

 for if the conclusions of the hypothesis were absurd 

 when applied to those regions of space about which we 

 even yet know little, they become grotesque when con- 

 nected with matter which we can investigate experi- 



