The eighty or more primordial elements are Nature’s alphabet with which she writes her “infinite book of secrecy.”  Science shows pretty conclusively that the character of the different substances, their diverse qualities and properties, depend upon the order in which the atoms and molecules are combined.  Change the order in which the molecules of the carbon and oxygen are combined in alcohol, and we get ether—­the chemical formula remaining the same.  Or take ordinary spirits of wine and add four more atoms of carbon to the carbon molecules, and we have the poison, carbolic acid.  Pure alcohol is turned into a deadly poison by taking from it one atom of carbon and two of hydrogen.  With the atoms of carbon, hydrogen, and oxygen, by combining them in different proportions and in different orders, Nature produces such diverse bodies as acetic acid, alcohol, sugar, starch, animal fats, vegetable oils, glycerine, and the like.  So with the long list of hydrocarbons—­gaseous, liquid, and solid—­called paraffins, that are obtained from petroleum and that are all composed of hydrogen and carbon, but with a different number of atoms of each, like a different number of a’s or b’s or c’s in a word.

What an enormous number of bodies Nature forms out of oxygen by uniting it chemically with other primary elements!  Thus by uniting it with the element silica she forms half of the solid crust of the globe; by uniting it with hydrogen in the proportion of two to one she forms all the water of the globe.  With one atom of nitrogen united chemically with three atoms of hydrogen she forms ammonia.  With one atom of carbon united with four atoms of hydrogen she spells marsh gas; and so on.  Carbon occurs in inorganic nature in two crystalline forms,—­the diamond and black lead, or graphite,—­their physical differences evidently being the result of their different molecular structure.  Graphite is a good conductor of heat and electricity, and the diamond is not.  Carbon in the organic world, where it plays such an important part, is non-crystalline.  Under the influence of life its molecules are differently put together, as in sugar, starch, wood, charcoal, etc.  There are also two forms of phosphorus, but not two kinds; the same atoms are probably united differently in each.  The yellow waxy variety has such an affinity for oxygen that it will burn in water, and it is poisonous.  Bring this variety to a high temperature away from the air, and its molecular structure seems to change, and we have the red variety, which is tasteless, odorless, and non-poisonous, and is not affected by contact with the air.  Such is the mystery of chemical change.

IV