PRINCIPLE OF UNIVERSAL CAUSATION. 161 



conservation- of matter and energy ; i.e. that matter and 

 its energy are indestructible by us ; and this is inferred 

 from the fact that amongst all the millions of experi- 

 ments, chemical analyses, and observations made by men, 

 not a single verifiable instance has ever been observed of 

 actual creation or annihilation of matter or force ; and 

 hence we infer that the total quantity of matter and energy 

 in the known universe is invariable. We know, from an 

 almost infinite number of most conclusive experiments, 

 that when substances are burned or converted into invi- 

 sible vapours or gases, the products possess the original 

 weight, and may be made to yield the original elements. 



IV. Several great, though lesser, principles flow from 

 this and the previous ones. Amongst them may be 

 mentioned persistency of phenomena, whether static or 

 dynamic ; physical, chemical, vital, or mental, or of form 

 or change of form. It is clear that if cause and effect 

 are indissolubly connected, and matter and energy are in- 

 destructible, persistency of natural phenomena must result. 

 This principle includes the first law of motion. A body 

 in a state of motion tends to continue in that state of 

 motion, and one in a state of rest tends to continue in a 

 state of rest ; and this is true not only of the mechanical 

 motion of masses, but also of molecular motion, including 

 that of physical, chemical, vital, and mental phenomena. 

 A body at a certain temperature tends to continue at 

 that temperature ; a substance burning tends to continue 

 to burn ; a heart beating tends to continue to beat ; a 

 brain thinking tends to continue to think, &c. Per- 

 sistency of structure and of form is seen in physical 

 science in the numerous phenomena of the structure and 

 shapes of crystals, 1 minerals, vegetables, and animals ; also 



1 A solution of common salt, however many times recrystallised, 

 always yields colourless cubes having similar properties. 



U 



