MATTER, LIVING FORCE AND HEAT. II 



rendered equal in brightness to the sun itself. And it 

 cannot be doubted that if the course of the earth were 

 changed so that it might fall into the sun, that body, so 

 far from being cooled down by the contact of a com- 

 paratively cold body, would actually blaze more brightly 

 than before in consequence of the living force with which 

 the earth struck the sun being converted into its equivalent 

 of heat. Here we see that our existence depends upon the 

 maintenance of the living force of the earth. On the other 

 hand, our safety equally depends in some instances upon 

 the conversion of living force into heat. You have, no 

 doubt, frequently observed what are called shooting-stars > as 

 they appear to emerge from the dark sky of night, pursue 

 a short and rapid course, burst, and are dissipated in shining 

 fragments. From the velocity with which these bodies 

 travel, there can be little doubt that they are small planets 

 which, in the course of their revolution round the sun, are 

 attracted and drawn to the earth. Reflect for a moment on 

 the consequences which would ensue, if a hard meteoric 

 stone were to strike the room in which we are assembled 

 with a velocity sixty times as great as that of a cannon- 

 ball. The dire effects of such a collision are effectually 

 prevented by the atmosphere surrounding our globe, by 

 which the velocity of the meteoric stone is checked and its 

 living force converted into heat, which at last becomes so 

 intense as to melt the body and dissipate it into fragments 

 too small probably to be noticed in their fall to the ground. 

 Hence it is that, although multitudes of shooting-stars 

 appear every night, few meteoric stones have been found, 

 those few corroborating the truth of our hypothesis 

 by the marks of intense heat which they bear on their 

 surfaces. 



