4 THE POPULAR SCIENCE MONTHLY. 



tbe soul, which, we are told, never dies, and which, if it exists, is 

 doubtless far removed from the influence of bodily diseases or injuries. 

 Therefore I beg you to understand that what I have to say relates 

 solely to the mind. Your souls are, doubtless, cared for by those 

 whose qualifications for instructing you in their management are 

 greater than any that I can claim. 



Now, what is mind ? Those of you who have thought much upon 

 the subject will not be surprised when I say that I do not know. There 

 may be othei's, however, who, though too polite to say so, may think 

 it a piece of impertinence for me to come here to speak of something 

 of the nature of which I am obliged at the very beginning of my dis- 

 course to confess my ignorance. But, if they thought thus, they 

 would be doing me great injustice, and it would be easy for me to 

 retaliate by asking them what a piece of wood is. Could they tell ? 

 Does any one know ? Does any one know what anything is ? There 

 are sixty-four elementary bodies of which the earth is composed, but 

 does any one know what a single one of them is ? Take one with 

 which you may be presumed to be especially familiar — iron. What 

 is it ? You do not know. You can describe it to me. You can point 

 out its properties. You can tell me where it comes from. Yes, and I 

 can do the same with the mind. I can tell you where it comes from, 

 describe its propex'ties, point out its manifestations, and you will 

 recognize mind as clearly as I should recognize the iron, the qualities 

 of which you should portray ; but, as to telling you what mind is, I 

 can not do it any more than you can tell me what iron is. 



Some of you are students of physics. If you were to present 

 yourselves in the class-room and ask your distinguished professor of 

 that branch of science to tell you what heat, light, electricity, magnet- 

 ism are, he would be obliged to tell you that he does not know, just 

 as I am forced to tell you that I do not know what mind is. But, 

 though he is ignorant of their essential natures, think of the vast 

 fields of knowledge he is able to open up to you by putting you in 

 possession of what is known of these forces ! 



Go into the chemical laboratory of your own noble university — in 

 honor of whose founder we are here to-day — and touch the two poles 

 of a galvanic battery. What is it that thrills through your bodies, 

 and perhaps even bui-ns the skin of your fingers ; or, even, if the cur- 

 rent be strong enough, strikes you dead on the instant ? Galvanism. 

 What is galvanism ? A force. Yes, and so is light a force, and 

 heat, and gravitation. But, when I am told this, I am just as far 

 from knowing what any one of the forces is as I was before. All 

 that you could do, if I persisted in asking for a fuller explanation, 

 would be to tell me something of the origin and properties of the 

 force in question, and in this way I should obtain some idea of its 

 characteristics, and should be in no danger of mistaking it for any 

 other force. That is what your Professor of Physics does for you. 



