36 WmTINGS OF JOSEPH HENRY. [1855- 



upon one of the outer planets of our system, the phenomena 

 of the motions of the heavenly bodies, as viewed from that 

 point, would have been so complex and apparently irregular, 

 that our present state of civilization (resting as it does on the 

 principles of science beginning with astronomy, the most 

 perfect) would not have existed : man would never have ar- 

 rived at the definite idea and the conclusive evidence of 

 the universality of causation. In other words, that amid 

 all the apparently confused and accidental occurrences which 

 we observe, a few simple laws (constantly diminishing in 

 number as our views become more extended) govern all 

 events, whether they be those which we refer to order and 

 succession, or those which in our ignorance we ascribe to 

 to chance. Astronomy is the most perfect of all the sciences, 

 not only because it has been longer studied, but more espec- 

 iall}'- because it is the simplest exhibition of the laws of force 

 and motion; and yet even in this science where all the data 

 are furnished, the introduction of a few conditions renders a 

 problem too complex for direct solution. For example, to 

 determine the path described and the time of revolution of 

 a single planet round the central body by the application of 

 the laws of motion and gravitation is a simple problem, 

 which was solved at an early period in the history of astron- 

 omy. When however a third body was introduced, such for 

 example as the moon, in addition to the earth and sun, the 

 problem baffled for a long time the skill of the first mathe- 

 maticians of the age; and even yet a direct a priori solution 

 of all the results which will be produced by the mutual action 

 of a series of planets revolving round the sun has not been 

 effected, and recourse is had to indirect methods of approx- 

 imation. Had man confined his observations to the complex 

 and multiform changes of the weather, the probability of his 

 ever arriving at a definite law would be far less than even in 

 the before mentioned case of astronomy ; for, though we are 

 assured that the motion of every atom of air is governed by 

 the same laws which direct the heavenly bodies, yet the 

 amount of perturbation and reciprocal action presented in 

 the case of myriads of atoms renders the probability of a com- 



