Colours, Lucretius' explanation of differences between, [ 18.]

Combustion, [ 141.]

Compounds, chemical conception of, [ 171.]

Conservation of mass, [ 164.]

Curie, her discovery of radium, [ 182.]

Dalton's additions to the Greek atomic theory, [ 21,] [ 172.]

Democritus, his saying about atoms, [ 15.]

Dephlogisticated air, [ 147.]

Destruction, thought by alchemists to precede restoration, [ 65,] [ 127.]

Electrons, [187-189,] [ 197,] [ 198.]