446 POPULAR SCIENCE MONTHLY 



2°. The eclipse happened at nine o'clock, says the astronomer. 



3°. The eclipse happened at the time deducible from the tables 

 constructed according to Newton's law, says he again. 



4°. That results from the earth's turning around the sun, says 

 Galileo finally. 



Where then is the boundary between the fact in the rough and the 

 scientific fact ? To read M. LeEoy one would believe that it is between 

 the first and the second stage, but who does not see that there is a 

 greater distance from the second to the third, and still more from the 

 third to the fourth. 



Allow me to cite two examples which perhaps will enlighten us a 

 little. 



I observe the deviation of a galvanometer by the aid of a movable 

 mirror which projects a luminous image or spot on a divided scale. 

 The crude fact is this: I see the spot displace itself on the scale, and 

 the scientific fact is this: a current passes in the circuit. 



Or again: when I make an experiment I should subject the result 

 to certain corrections, because I know I must have made errors. These 

 errors are of two kinds, some are accidental and these I shall correct 

 by taking the mean; the others are systematic and I shall be able to 

 correct those only by a thorough study of their causes. The first result 

 obtained is then the fact in the rough, while the scientific fact is the 

 final result after the finished corrections. 



Keflecting on this latter example, we are led to subdivide our 

 second stage, and in place of saying: 



2. The eclipse happened at nine o'clock, we shall say : 



2a. The eclipse happened when my clock pointed to nine, and 



2&. My clock being ten minutes slow, the eclipse happened at ten 

 minutes past nine. 



And this is not all: the first stage also should be subdivided, and 

 not between these two subdivisions will be the least distance; it is 

 necessary to distinguish between the impression of obscurity felt by 

 one witnessing an eclipse, and the affirmation; it grows dark, which 

 this impression extorts from him. In a sense it is the first which is the 

 only true fact in the rough, and the second is already a sort of 

 scientific fact. 



Now then our scale has six stages, and even though there is no 

 reason for halting at this figure, there we shall stop. 



What strikes me at the start is this. At the first of our six stages, 

 the fact, still completely in the rough, is, so to speak, individual, it is 

 completely distinct from all other possible facts. From the second 

 stage, already it is no longer the same. The enunciation of the fact 

 would suit an infinity of other facts. So soon as language intervenes, 

 I have at my command only a finite number of terms to express the 



