U PRODUCTION SECT. XIV. 2. 5. 



to another, it follows, that they have alike the property of pof~ 

 fefling heat or motion. 



Hence the fpirit of animation, at the time it communicates 

 or receives motion from folid bodies, mult itfelf poflefs fome 

 property of folidity. And in confequence at the time it re- 

 ceives other kinds of motion from light, it mud poflefs that 

 property, which light poflefles, to communicate that kind of 

 motion ; and for which no language has a name, unlefs it may 

 be termed Viability. And at the time it is flimulated into oth- 

 er kinds of animal motion by the particles of fapid and odorous 

 bodies affecting the fenfes of tafte and fmell, it mud refemble 

 thefe particles of flavour, and of odour, in poflefling fome fim- 

 ilar or correfpondent property ; and for which language has no 

 name, unlefs we may ufe the words Saporofi'y and Odorofity 

 for thofe common properties, which are poflefled by our organs 

 of tafte and fmell, and by the particles of fapid and odorous 

 bodies; as the words Tangibility and Audibility may exprefs 

 the common property poflefled by our organs of touch, and of 

 hearing, and by the folid bodies, or their vibrations, which af- 

 fect thofe organs. 



5. Finally, though the figures of bodies are in truth refern- 

 bled by the figure of the part of the organ of touch, which is 

 ftimulated into motion ; and that organ refembles the folid 

 bodv, which ftimulates it, in its property of folidity ; and 

 though the fen e of hearing refembles the vibrations of external 

 bodies in its capability of being ftimulated into motion by thofe 

 vibrations ; and though our other organs of fenfe refemble the 

 bodies that itimulate them, in their capability of being ftimu- 

 lated by them ; and we hence become acquainted with thefe 

 properties of the external world ; vet as we can repeat all thefe 

 motions of our organs of fenfe by the efforts of volition, or in 

 confequence of the fenfation of pleafure or pain, or by their af- 

 fociation with other fibrous motions, as happens in our reveries 

 or in fleep, there would ftill appear to be iome difficulty in 

 demonftrating the exiftence of any thing external to us. 



In our dreams we cannot determine this circumftance, be- 

 caufe our power of volition is fufpended, and the (timuli of ex- 

 ternal objects are excluded ; but in our waking hours we can 

 compare our ideas belonging to one fenfe with thofe belonging to 

 another, and can thus diftinguifh the ideas occafioned by irrita- 

 tion from thofe excited by fenfation, volition or aflbciation. 

 Thus if the idea of the fweetnefs of fugar fhould be excited in 

 our dreams, the whitenefs and hardnefs of it occur at the fame 

 time by aflbciation ; and we believe a material lump of fugar 

 prefent before us. But if, in our waking hours, the idea of the 



fweetnefs 



