First with fond gaze blue fields of air they sweep, Or pierce the briny chambers of the deep; 10 Earth's burning line, and icy poles explore, Her fertile surface, and her caves of ore; Or mark how Oxygen with Azote-Gas Plays round the globe in one aerial mass, Or fused with Hydrogen in ceaseless flow Forms the wide waves, which foam and roll below. [Footnote: _How Oxygen_, l. 13. The atmosphere which surrounds us, is composed of twenty-seven parts of oxygen gas and seventy-three of azote or nitrogen gas, which are simply diffused together, but which, when combined, become nitrous acid. Water consists of eighty-six parts oxygen, and fourteen parts of hydrogen or inflammable air, in a state of combination. It is also probable, that much oxygen enters the composition of glass; as those materials which promote vitrification, contain so much of it, as minium and manganese; and that glass is hence a solid acid in the temperature of our atmosphere, as water is a fluid one.] Next with illumined hands through prisms bright Pleased they untwist the sevenfold threads of light; Or, bent in pencils by the lens, convey To one bright point the silver hairs of Day. 20 Then mark how two electric streams conspire To form the resinous and vitreous fire; Beneath the waves the fierce Gymnotus arm, And give Torpedo his benumbing charm; Or, through Galvanic chain-work as they pass, Convert the kindling water into gas. [Footnote: _Two electric streams_, l. 21. It is the opinion of some philosophers, that the electric ether consists of two kinds of fluids diffused together or combined; which are commonly known by the terms of positive and negative electricity, but are by these electricians called vitreous and resinous electricity. The electric shocks given by the torpedo and by the gymnotus, are supposed to be similar to those of the Galvanic pile, as they are produced in water. Which water is decomposed by the Galvanic pile and converted into oxygen and hydrogen gas; see Additional Note XII. The magnetic ether may also be supposed to consist of two fluids, one of which attracts the needle, and the other repels it; and, perhaps, chemical affinities, and gravitation itself, may consist of two kinds of ether surrounding the particles of bodies, and may thence attract at one distance and repel at another; as appears when two insulated electrised balls are approached to each other, or when two small globules of mercury are pressed together.]