136 The Evolution of Chemistry. 



strument by astronomers has revealed the strange fact that 

 the number of elements increases with. the progress of a 

 nebula toward stardom. Another remarkable fact is that as 

 the numbers do increase it is from those with light atomic 

 weights to those with heavy ones. Who would have thought 

 a century ago that man would ever be able to analyze the 

 matter stars are made of? To-day it is an accomplished 

 fact, and the revelation given teaches us that what we call 

 matter is a product of something unknown and indescriba- 

 ble by us. That from which matter grew must have been 

 wholly unlike matter as we know it. 



Many facts seem to indicate that the successive steps of 

 integration among the atoms while forming followed well- 

 known chemical laws. Lately, however, an English chemist 

 named Crookes has shown that it is possible to take a large 

 mass of the molecules of a single element, and by successive 

 sif tings separate them into two classes with slight shades of 

 difference in qualities. Minute fractional differences of this 

 kind go to show that while known methods of chemical 

 grouping may have been used in their development, yet 

 there is some different law at work from any as yet dis- 

 covered. The fact, too, that Prout's supposed law "has not 

 been confirmed by the most careful determinations of atomic 

 weights, points the same way. 



While many of the heavier elements are multiples by 

 whole numbers of hydrogen, most of them do not seem to 

 be so. The spectroscope points to the existence in the sun 

 of an element lighter than hydrogen, and that has been 

 called helium. If this or a lighter element still has been 

 the starting point, Prout's law may yet prove to be true for 

 all elements, as it is now for a goodly number. It would 

 give us a fractional part of a hydrogen atom as point of 

 comparison. 



To understand the bearings of this hypothesis of Prout's 

 on evolution it is necessary to know something about how 

 atoms link themselves together to form molecules and what 

 compound radicals are. During the development of the 

 science of chemistry this branch of the tree has borne more 

 fruit than any other, and yet it is the one that pronounces 

 most emphatically in favor of the physical existence of 

 atoms and molecules as real beings. We have already seen 

 that all the elements bear names, and that one letter (or 

 sometimes two) of the Latin name is used as a symbol. Tne 

 chemist undertakes to group on paper these symbols in some 



