46 Wisconsin Academy of Sciences, Arts^ and Letters. 



on the length of snch instaUment^ it is desirable to establish a 

 scale by which it can be measured. I therefore invite an ef- 

 fort to determine the proper 



VII. rXIT OF THOUGHT-MEASUREMENT. 



Snj^pose that in addressing nie you utter merely the phrfise 

 "The sun" ; and suppose further that you successfully rouse in 

 my mind the idea for which this phrase is connnonly used ; sup- 

 pose too that from your utterance I infer that you also are think- 

 ing of the same idea. It must still be admitted that the ideal 

 total common to our minds is very meager, too small indeed to 

 be worth your labor in expression or mine in apprehension. The 

 price "for your thoughts" being currently quoted as " a penny," 

 the market value of a single thought-factor can hardly be great 

 enough to warrant the expense of transportation. 



Suppose now you go further, saj^ing "The sun, the moon." 

 My mind is now enriched by two ideas, which otherwise I might 

 not enjoy. I may furtlier correctly infer that you also have 

 both in mind. But the market value of your mental output is 

 presumably only doubled. It is safe to say that, were language 

 able only to deal with pairs of ideas, it would not exist in a form 

 deserving the name. Two ideas thus summoned together may, 

 it is true, induce us both to perform upon them mental opera- 

 tions. But nothino' assures us that these would be the same or 

 that, even if they were the sailie, we should be sure that they were 

 so. Such operations, the essentials of thought, are not sug- 

 gested by the words of my example. These words indeed give 

 only thought-data ; and these data alone have not sufficient value 

 to justify expression. 



The passage of attention from one idea to another is con- 

 veniently known as a mental transit. That you have made such 

 a transit from the idea of the sun to that of the moon, I raay 

 of course infer. But my knowledge, even thus augmented, is 

 quite unsatisfactory. I care little to learn that you have merely 

 experienced a succession of ideas, or where the succession began, 

 or where it ended. If anything in such an experience can in- 

 terest me, it will be the impressions of the mental traveller. 

 You must give me something of the personal element that sat- 

 iirates the "Sentimental Journey." 



