ARE THE ELEMENTS ELEMENTARY? 469 



supf)Osed elements in their relations to the various modes of energy? 

 Perliaps in the discussion of this problem Gustavus Hiurichs would 

 stand first. His conclusions may be easily questioned, but the ability 

 and ingenuity displayed in reaching them cannot be denied. 



To the general reader, or to the beginner in chemistry, the difficul- 

 ties confronting the unitary view of matter may seem to be very great. 

 Doubtless they are ; but then every side of the subject is beset with 

 difficulties. Obstacles must be surmounted, and the worst are not in 

 this direction. The mind unused to speculations of this sort will prob- 

 ably encounter its greatest embarrassment in trying to understand 

 how oue substance alone can assume such a diversity of forms. That 

 such a thing is within the limits of possibility, may be illustrated by 

 reference to the facts of allotropy and isomerism. Quite a number of 

 our present elements are known to be capable of existing in a variety 

 of dissimilar modifications. Carbon is found as charcoal, graphite, 

 and diamond ; phosphorus exists both in its white and in its red modi- 

 fications ; oxygen is allotropic as ozone. Similar examples are fur- 

 nished by arsenic, selenium, and, very notably, by sulpliur. Among 

 compounds, especially in organic chemistry, many cases occur in which 

 several different bodies have precisely the same elementary composi- 

 tion. For instance, the essential oils of rose, bergamot, orange, lemon, 

 lavender, turpentine, rosemary, nutmegs, myrtle, peppermint, etc., 

 unlike as they may be in outward properties, are all composed of car- 

 bon and hydrogen in exactly the same percentages. The same atoms 

 occur, but differently arranged. Many other sets of isomeric bodies 

 are known in which this diversity of atomic arrangement can be dis- 

 tinctly traced, and the reasons for difference clearly pointed out. The 

 limitations of space prevent their description here. 



Now, since a single element may exist in several different forms, 

 and since the same atoms can unite together so as to produce com- 

 pounds very unlike each other, the chief objection to the unitary view 

 is removed. Why may not all the so-called elements be allotropic 

 modifications of one, or else isomeric bodies formed by the union of 

 two or three such modifications ? Such a supposition is by no mea'ns 

 absurd, although, to be sure, it is not capable of rigid demonstration. 

 It is only a speculation, but then within it are some fair probabilities. 

 These may be strengthened by an appeal to spectroscopic evidence, 

 and to the prevalent hypothesis concerning the origin of our planet. 



If we examine the spectra of our supposed elements, we shall no- 

 tice no more striking fact than the extent to which they differ in com- 

 plexity. Some bodies give spectra of only one or two lines, while 

 others are represented by hundreds. This atom emits light of a sin- 

 gle wave-length, that one gives out rays of nearly half a thousand 

 different kinds. Now, what do these facts mean ? Do they indicate 

 structural differences within molecules such that each bright line in a 

 spectrum corresponds to a true element ? Such a notion, if true, 



