194 Mr. G, Johnstone Stoney [Feb. 6, 



This is intimately connected with another shortcoming of our 

 minds, that the quantity of thought which can come wdthin our con- 

 sciousness at any one time is limited. We find that by what we call 

 attending we can exercise a choice amid such suitable materials as 

 are present within the brain ; but that by choosing some we exclude 

 others. In a large assembly a babel of sounds may reach our brain : 

 by attention we can bring more emphatically within our conscious- 

 ness some of these sounds, and thereupon the rest pass partially 

 beyond consciousness. Before we make our choice we hear a confused 

 and much louder noise. After we set ourself to listen to one speaker 

 out of many, to the rustle of a particular silk dress, or to any other of 

 the tangle of sounds that assail us, those w^e have directed our atten- 

 tion to become more distinctly heard, the rest less heard, those we 

 have selected are brought far within the boundary of consciousness 

 and will be long remembered, the others pass partly beyond and if 

 heard at all are soon forgotten — indeed they may pass entirely beyond 

 our consciousness and be wholly unnoticed, if our attention to the 

 selected sounds is sufiiciently intense. 



A very curious phenomenon closely related to the foregoing 

 occurs when the clock strikes w^hile we are so preoccupied, that 

 though we hear that it is striking, we do not know what o'clock has 

 struck. If just after it has struck, " with the sound still ringing in 

 our ears," we wish to know the hour, it is generally possible to go 

 over in memory what has recently been heard and to count the strokes, 

 the number of which was until then unknown. 



We often avail ourselves of these jDroperties of our minds. The 

 way in which we dismiss a thought from our mind is by vigorously 

 devoting our attention to something else. It is in fact the only way 

 we have of doing so. 



By carefully observing matters of this kind we may satisfy our- 

 selves that the thought of w^hich we are conscious is a portion of a 

 larger body of thought of the same kind lying close to our conscious- 

 ness, in fact within our brain. The considerations brought forward 

 in the earlier part of this discourse, give us reason strongly to suspect 

 that there is also present within the brain a vastly more extensive 

 body of thought differing, at all events in time relations, from any 

 thought of which we can be conscious ; and further that the thought 

 that is present in the brain, whether the little that we are conscious 

 of or the rest, is but one (hoy) of a boundless ocean. 



Here I must end. I dwelt chiefly on the first part of my subject 

 as being the most appropriate to be fully discussed in the hall in 

 which we are here assembled, and this has left little time for expound- 

 ing the second. If time had allowed, the second part would have 

 led us through considerations of supreme interest, and its issue is to 

 reveal to us a vision of the universe of unsurpassed sublimity. 



[G. J. S.] 



