170 THE ANATOMY OF SCIENCE 



of the other method. After the beauty and pre- 

 cision of their own type of experiments and de- 

 ductions they do not see the cogency of infer- 

 ences drawn from such a vague chaos. Some 

 years ago I discovered a universal tendency of 

 electrons to pair with one another in the mole- 

 cule and in the atom, and this conclusion is now 

 pretty generally accepted by chemists, but it 

 seems to conflict with certain equations for sta- 

 bility, and for this reason it has not been fully 

 accepted, as far as I know, by any physicist. 

 Yet not merely the chemical facts, but the ob- 

 servations by the physicists themselves upon 

 ionizing potentials and spectroscopy, show no- 

 where so remarkable a distinction as that be- 

 tween substances which have an even and those 

 which have an odd number of electrons in the 

 outer shell of the atom. 



It must be admitted that science has its 

 castes. The man whose chief apparatus is the 

 differential equation looks down upon one who 

 uses a galvanometer, and he in turn upon those 

 who putter about with sticky and smelly things 

 in test tubes. But all of these, and most biolo- 

 gists too, join together in their contempt for 

 the pariah who, not through a glass darkly, but 

 with keen unaided vision, observes the massing 



