CARBON—LITTLE 241 
ing works. Thus, without carbon so employed, the route to San 
Francisco might still be around the Horn. 
COMBUSTION AND OXIDES OF CARBON 
The making of fire was perhaps the greatest achievement of the 
human race, and, though there has been no posthumous award of 
medals to Prometheus, the phenomena of combustion include some of 
the most fundamental chemical changes with which we are 
acquainted. All of the ordinary forms of combustion, upon which 
we depend for light and heat, involve the burning of carbon or of 
compounds of carbon and hydrogen. Even the diamond may be 
burned in oxygen, and the product of its combustion is carbon di- 
oxide, differing in no respect from the CO, produced when charcoal 
is burned in air. When hydrocarbons burn the ultimate products of 
combustion are carbon dioxide and water. 
During all the long centuries which preceded the Welsbach mantle 
and the tungsten filament practically all artificial light was derived 
from incandescent carbon. It glowed in the firelight within the 
caves which sheltered the Neanderthal man and later in the smoky 
flare of pine-knot torches, rude oil lamps, and rushlights. In the 
flickering flames of many candles it lent brilliance to the courtly fétes 
of Versailles, and the Argand burner, the gas flame, and the carbon 
filament have brought light into our own homes. There is an almost 
unthinkable complexity to flame within which molecular systems are 
disrupted as their vibrating atoms rush, with the discharge of ions 
and electrons, to form new systems while radiating energy as heat 
and light. Since light has always been regarded as the symbol of 
joy and life-giving power, it is not surprising that fire was sacred 
and adorable in primitive religions. The Parsees adore fire as the 
visible expression of Ahura-Mazda. The Brahmans worship it as 
that “which knowest all things.” In the Jewish Holy of Holies 
was a “cloud of light ” symbolical of the presence of Yahweh. Jew- 
ish synagogues have their eternal lamps as the Greeks and Romans 
had their perpetual and sacred fires. In Christianity fire and light 
have always been conceived as symbols of the divine nature and 
presence. Human history and literature teem with their romantic 
associations. What pictures are called to mind by the mere mention 
of vestal fires in the temples, of watch fires on the hill, of camp fires 
in the forest or in the field with troops. The driftwood fire depicts 
the wreck of stranded ships that missed the gleam of the beacon 
which brought others safely to port. Candles and altar fires, the 
pillar of smoke, and the burning bush have their deep religious sig- 
nificance. 
The extinction of lights marks the end of the ceremony of excom- 
munication, while the symbol of reconciliation is the handing to the 
