The Romance of Modern Chemistry

HIGH TEMPERATURES by enlarging the cavity of the lime furnace, and making a little platform of |-inch plates of magnesia and carbon, arranged alternately. Using a device of this sort, Moissan was able to study the behaviour of a large number of substances at temperatures up to 6000° Fahrenheit. In the earlier part of this chapter it was said that, compared with zinc at least, copper was not volatile. Things are quite different, however, at the temperature of the electric furnace, as appeared from Moissan’s experiments. A piece of copper weighing nearly four ounces was put in a carbon crucible in the furnace, which was then warmed up for five minutes by a big current. Soon after the current was turned on, dazzling flames, 18 inches long, burst out violently through the openings at the ends of the furnace. These flames were due to copper vapour burning in the air; and it was found after the experiment was over that the copper left in the furnace now weighed only 3 ounces, 1 ounce of the metal having been converted into vapour. Similar and equally surprising results were obtained with such refractory metals as silver, gold, and platinum. One of the most surprising things accomplished in Moissan’s electric furnace was the vaporisation of silica. This substance, as the reader may already be aware, is the oxide of the element silicon, and is the main con- stituent of sand and quartz. Indeed, quartz is nearly pure silica. It is melted with the greatest ease in the electric furnace, and after seven to eight minutes issues through the openings as a bluish smoke or vapour— another proof of the really fervent heat which is generated in this way. While the electric furnace has astonished us by reveal- ing the volatility of even the most staid and refractory 199