Stoney — Natural Science and Ontology. 505 



degrees of precision. The colour sensations which come into 

 existence when I look out of the window into the park which is 

 before my house, appear to me to be at different distances from 

 the sensations that accompany the act of looking, viz. those caused 

 by the occasional winking of my eyes, and by my adjusting them 

 upon the several objects. These latter may be called my central 

 sensations, as they are those which fix the centre of space as I 

 apprehend it. The colour sensations appear also at different 

 distances and in different directions from one another, the green of 

 the grass appearing in a different situation from the sensation of 

 the white blossoms of a cherry tree in flower, from the sensation 

 of blue in the sky, or of the grey pebbles of the gravelled walks. 

 Now, this localising of sensations has arisen through synthesis, 

 and is accomplished instinctively by our modern developed and 

 trained minds, or rather partly by our minds and partly for them 

 by the unconscious 1 cerebration which is associated with them. 



The instinct which impels us to assign a position in space to 

 sensations affects our visual and tactual sensations most, including 

 under the latter term our muscular sensations as well as sensations 

 of roughness, smoothness, resistance, hardness, softness, and some 

 others. We also perceive it conspicuously in the allied sensations 

 of tickling, warmth, coolness, pain, and several others. We 

 localise with somewhat less precision our sensations of taste and 

 smell : and of all our more conspicuous sensations sound is that 

 which we least refer to a definite position. We have less power 

 of doing so than many other animals who are furnished with ears 

 which can be turned so as to distinguish the direction of sound, 

 and far less power than some nocturnal insects who by their 

 feathery antennae, which are their auditory apparatus, are able to 

 determine the direction of a sound with a precision approaching 

 that of eyesight. In man there are but slender materials for the 

 synthesis. 



In order to apprehend clearly how much has been accomplished 

 by synthesis, it is advisable that we should scrutinise more closely 

 space relations, and man's instinctive judgments about them : and 

 as these judgments are a more conspicuous factor of my visual and 

 tactual perceptions than of others, it will be instructive to treat 



1 That is, cerebration that is not within my consciousness. 



