85 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, muft itfelf pofTefs fome 

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

 ceives other kinds of motion from light, it muft pofTefs that 

 property, which light pofTefTes, to communicate that kind of 

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

 be termed Vifibility. 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 muft refemble 

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

 ilar or correfpondent property ; and for which language has no 

 name, unlefs we may ufe the words Saporofity and Odorofity 

 for thofe common properties, which are pofTefled 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 pofiefTed 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 refem- 

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

 flimulated into motion ; and that organ refembles the folid 

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

 though the fenfe 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 ftimulate them, in their capability of being ftimu- 

 lated by them ; and we hence become acquainted with thefe 

 properties of the external world ; yet 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 (till appear to be fome 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 ftimuli 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 affociation. 

 f the idea of the fweetnefs of fugar mould be excited in 

 the v/birenefs and hardnefs of it occur at the fame 

 time by aiTociation -, and we believe a material lump of fugar 

 prchxit before u>. But if, in our waking hours, the iclea of the 



fweetnefs 



