The use of such furnaces has very considerably diminished, owing to the general introduction of coal-gas for heating purposes in laboratories, which has been rendered possible by the invention of the Bunsen burner, in which the mixture of air and gas giving the least luminous but most powerfully heating flame is effected automatically by the effluent gas.
Then, by the use of another piece of platinum as anode, mercury is electrolytically deposited upon the platinum, which may also be amalgamated by making it white hot in a Bunsen flame and plunging it in mercury.
Strontium salts may be recognized by the characteristic crimson colour they impart to the flame of the Bunsen burner and by the precipitation of the insoluble sulphate.
In April 1833 occurred what is known as the Frankfort Insurrection (Frankfurter Attentat), in which a number of insurgents led by Georg Bunsen attempted to break up the diet.
Gouy, who forced the air before it entered the Bunsen burner, through a spray produce containing a salt in solution.
Manganese salts can be detected by the amethyst colour they impart to a borax-bead when heated in the Bunsen flame, and by the green mass formed when they are fused with a mixture of sodium carbonate and potassium nitrate.
In the ordinary laboratory the Bunsen flame has become universal, and a number of substances, such as the salts of the alkalis and alkaline earths, show characteristic spectra when suitably placed in it.
Detection and Estimation.-Most calcium compounds, especially when moistened with hydrochloric acid, impart an orange-red colour to a Bunsen flame, which when viewed through green glass appears to be finch-green; this distinguishes it in the presence of strontium, whose crimson coloration is apt to mask the orange-red calcium flame (when viewed through green glass the strontium flame appears to be a very faint yellow).
A long tour in Italy in 1828 was the beginning of his intimacy with Bunsen and did much to develop his knowledge of art and love of antiquity.
Indium salts can be recognized by the dark blue colour they give in the flame of the Bunsen burner; and by the white beads of metal and the yellow incrustation formed when heated on charcoal with sodium carbonate.