424- Mode of conveying Perceptions.. [Book X. 



perceived by the mind, the trace or veftige it leaves 

 behind is called an idea. 



Whether the mode of conveying perceptions from 

 the fenfes to the underftanding, is by a vibratory mo- 

 tion of the nerves * or by any other means, is of no 

 confequence to the prefent inquiry. It is fufficient to 

 fay, that the fenfes are firft affected by external ob- 

 jects, that thefe impreffions leave behind them veftiges 

 which are called ideas, and from the natural or volun- 

 tary combination of two or more of thefe, a new idea 

 may be formed. 



* Such is the theory of the ingenious, but viiionary Hartley, 



