f 1 8 Similarity of mental and physical phenomena. 



inanimate matter by living bodies and in mental 

 action, so have modern inventions demonstrated the 

 possibility of the performance by inanimate sub- 

 stances and apparatuses, of the functions, not only of 

 our bodily organs, (as of locomotion by the steam 

 engine,) but also of our senses and intellect, and in 

 some cases, to a degree far surpassing unaided human 

 power. Apparatus, sensitive to sound, have been con- 

 structed, as in the microphone and singing-flames ; 

 others capable of reproducing articulate speech, as in 

 the phonograph, telephone, etc. ; others again sensitive 

 to light, as in the production of visible images by 

 photography, and reproducing them at a distance 

 through wires by means of the photophone ; the power 

 of indicating or foretelling future events has also been 

 embodied in instruments called " tide predictors," and 

 that of evolving inferences has been shewn in Jevon's 

 " Logical machine." 



The various facts mentioned in this chapter prove 

 that mind agrees with the various forms of physical 

 energy in many essential points, and obeys many of 

 the same laws or principles. Examine whatever gen- 

 eral phenomena of the mind we may, we can always 

 detect some apparent or real connection of them with 

 the great principles of inorganic nature ; and in order 

 to prove the dependence of them upon the great 

 principles of science it is not necessary to show that 

 all such actions are subject to those principles. Until 

 the whole is explained however, there will always 

 remain mysterious phenomena to cavil about. 



