n<S PRODUCTION OF IDEAS. SECT.XIV. 2. 



We acquire our tangible ideas of objects either 

 by the fimple preflure of this organ of touch againft 

 a folid body, or by moving our organ of touch 

 along the furface of it. In the former cafe we learn 

 the length and breadth of the object by the quan- 

 tity of our organ of touch, that is imprefied by it : 

 in the latter cafe we learn the length and breadth 

 of objects by the continuance of their preflure on 

 our moving organ of touch. 



It is hence, that we are very flow in acquiring 

 our tangible ideas, and very flow in recollecting 

 them ; for if I now think of the tangible idea of a 

 cube, that is, if I think of its figure, and of the 

 folidity of every part of that figure, I muft con- 

 ceive ipyfelf as pafling my fingers over it, and feem 

 in fome meafure to feel the idea, as 'I formerly did 

 the impreflion, at the ends of them, and am thus 

 very flow in diftinctly recollecting it. 



When a body comprefles any part of our fenfe 

 of touch, what happens ? Firft, this part of our 

 fenforium undergoes a mechanical compreflion, 

 which is termed a iHmulus ; fecondly, an idea, or 

 contraction of a part of the organ of fenfe is ex- 

 cited ; thirdly, a motion of the central parts, or of 

 the whole fenforium, which is termed fenfation, is 

 produced ; and thefe three conilitute the percep- 

 tion of folidity. 



2. Of Figure, Motion, Time, Place, Space, Number. 



No one will deny, that the medulla of the brain 

 and nerves has a certain figure ; which, as it is 

 diffufed through nearly the whole of the body, 

 muft have nearly the figure of that body. Now it 

 follows, that the fpirit of animation, or living prin- 

 ciple, as it occupies this medulla, and no other 

 part, (which is evinced by a great variety of cruel 

 experiments on living animals,) it follows, that 



this 



