Dr. J. H. Mayer on Celestial Dynamics. 247 



vis viva which he possesses in consequence of his rotation. 

 Assuming his density to be uniform throughout his mass, and 

 his period of rotation twenty-five days, it is equal to 182,300 

 quintillions of kilogrammetres (Km). But for one unit of heat 

 generated, 367 Km are consumed; consequently the whole 

 rotation-effect of the sun could only cover the expenditure of heat 

 for the space of 183 years. 



IV. The Organization of the Planetary System contains the 

 Cause of the Sun's Heat. 



The space of our solar system is filled with a great number of 

 ponderable objects, which have a tendency to move towards the 

 centre of gravity of the sun ; and in so doing, their rate of motion 

 is more and more accelerated. 



A mass, without motion, placed within the sphere of the sun's 

 attraction, will obey this attraction, and, if there be no disturbing 

 influences, will fall in a straight line into the sun. In reality, 

 however, such a rectilinear path can scarcely occur, as may be 

 shown by experiment. 



Let a weight be suspended by a string so that it can only 

 touch the floor in one point. Lift the weight up to a certain 

 height, and at the same time stretch the string out to its full 

 length ; if the weight be now allowed to fall, it will be observed, 

 almost in every case, not to reach at once the point on the floor 

 towards which it tends to move, but to move round this point 

 for some time in a curved line. 



The reason of this phenomenon is that the slightest deviation 

 of the weight from its shortest route towards the point on the 

 floor, caused by some disturbing influence such as the resistance 

 of the air against a not perfectly uniform surface, will maintain 

 itself as long as motion lasts. It is nevertheless possible for the 

 weight to move at once to the point j the probability of its doing 

 so, however, becomes the less as the height from which it is 

 allowed to drop increases or the string, by means of which it is 

 suspended, is lengthened. 



Similar laws influence the movements of bodies in the space 

 of the solar system. The height of the fall is here represented 

 by the original distance from the sun at which the body begins 

 to move ; the length of the string by the sun's attraction, which 

 increases when the distance decreases ; and the small surface of 

 contact on the floor by the area of the section of the sun's 

 sphere. If now a cosmical mass within the physical limits of 

 the sun's sphere of attraction begins its fall towards that 

 heavenly body, it will be disturbed in its long path for many 

 centuries, at first by the nearest fixed stars, and afterwards by 

 the bodies of the solar system. Motion of such a mass in a 



