46 THE SCIENCE OF LOGIC 



establish that they will combine only in the proportion of I to 35-5 by 

 weight, or which is the same of i to I by volume. When those proportions 

 are brought together under the influence of sunlight no matter how little or 

 great the absolute quantities may be, milligrammes, centigrammes, decigrammes 

 the combination will take place. On the other hand, when those proportions 

 are not maintained, the quantity of the one which is in excess of its due propor 

 tion to the total quantity of the other, will remain over, unaffected by the 

 combination. 



&quot; Here, then, are other facts in presence of which the observer finds him 

 self : Two definite gases, mixed in definite proportions of i to i by volume 

 or i to 35-5 by weight, combine under the action of sunlight the absolute 

 quantities of each being indifferent to the result and indefinitely variable. 

 Neither of these gases, mixed with any other gases, combine with the latter in 

 the same conditions and proportions ; if mixed with each other in any other 

 proportions than those indicated, they will not combine completely, but will 

 leave the surplus above the proportion unmolested. Further, the chemist 

 remarks that, after the combination, one volume of hydrogen and one volume 

 of chlorine, combining under definite conditions of temperature and pressure, 

 yield two volumes of hydrochloric acid gas. 



&quot; Are all those facts which recur repeatedly in similar circumstances 

 the result of mere chance coincidences of disconnected and indifferent causes ? 

 They are not : they cannot be. Reason will not admit that any such complex, 

 harmonious, stable series of facts could be due to chance. They must be the ex 

 pression of a law ; they must find their sufficient reason in the nature of the 

 combining bodies. 



&quot; The chemist finds this sufficient reason in what he calls the affinities 

 of the reacting bodies ; the metaphysician, in properties inherent in the 

 nature of those bodies, and indicative of the energies of those natures. The 

 language is different, but at bottom the idea is the same : There are in the 

 world such complex, harmonious, stable series of facts as cannot be due to 

 chance activities, but must be the result and expression of natural laws ; and 

 the formation of hydrochloric acid from hydrogen and chlorine is a mani 

 festation of such a law. 



&quot; Thus it is that, from the total complex groups of circumstances in which 

 he has witnessed the formation of hydrochloric acid, the chemist abstracts or 

 gathers by induction the truth that hydrogen and chlorine have the property 

 of combining in the proportions indicated, with a disengagement of 22 calories 

 of heat for the formation of each molecule-gramme of hydrochloric acid. The 

 combination being, moreover, found to be independent of the particular place 

 and time, and of the absolute quantities of the bodies used, he can foretell 

 with certainty that always and everywhere those gases will combine in those 

 definite proportions to form the compound body, when submitted to the action 

 of the sunlight under the same general conditions. 



&quot; In a word, the law of hydrogen and chlorine is to combine, always and 

 everywhere, under the above-mentioned conditions. The chemist who has ob 

 served all the facts and extracted that law from them has made an induction.&quot; 



&quot;Thus, the chemist has verified his hypothesis that the two gases, 

 hydrogen and chlorine, have the natural property of combining in the definite 



