448 POPULAR SCIENCE MONTHLY 



will not be you when you say to me: I have spoken to you in English 

 or in French. 



Is there something to change in all that when we pass to the 

 following stages ? When I observe a galvanometer, as I have just said, 

 if I ask an ignorant visitor: Is the current passing? He looks at the 

 wire to try to see something pass; but if I put the same question to 

 my assistant who understands my language, he will know I mean: 

 Does the spot move? and he will look at the scale. 



What difference is there then between the statement of a fact in 

 the rough and the statement of a scientific fact? The same difference 

 as between the statement of the same crude fact in French and in 

 German. The scientific statement is the translation of the crude 

 statement into a language which is distinguished above all from the 

 common German or French, because it is spoken by a very much 

 smaller number of people. 



Yet let us not go too fast. To measure a current I may use a very 

 great number of types of galvanometers or besides an electro dynamom- 

 eter. And then when I shall say there is running in this circuit 

 a current of so many amperes, that will mean: if I adapt to this 

 circuit such a galvanometer I shall see the spot come to the division a; 

 but that will mean equally: if I adapt to this circuit such an electro- 

 dynamometer, I shall see the spot go to the division o. And that will 

 mean still many other things, because the current can manifest itself 

 not only by mechanical effects, but by effects chemical, thermal, 

 luminous, etc. 



Here then is one same statement which suits a very great number 

 of facts absolutely different. Why? It is because I assume a law 

 according to which, whenever such a mechanical effect shall happen, 

 such a chemical effect will happen also. Previous experiments, very 

 numerous, have never shown this law to fail, and then I have under- 

 stood that I could express by the same statement two facts so invari- 

 ablv bound one to the other. 



When I am asked: Is the current passing? I can understand that 

 that means : Will such a mechanical effect happen ? But I can under- 

 stand also: Will such a chemical effect happen? I shall then verify 

 either the existence of the mechanical effect, or that of the chemical 

 effect; that will be indifferent, since in both cases the answer must be 

 the same. 



And if the law should one day be found false? If it was per- 

 ceived that the concordance of the two effects, mechanical and chemical, 

 is not constant? That day it would be necessary to change the scien- 

 tific language to free it from a grave ambiguity. 



And after that? Is it thought that ordinary language by aid of 

 which are expressed the facts of daily life is exempt from ambiguity? 



