—, medal for discovery of, by the King of Denmark, xxiii, 391.
Commun, J. du, on the causes of fresh water springs, xiv, 174.f
—, hypothesis on volcanoes and earthquakes, xv, 12.f
—, — —, objections to, xv, 25.
—, — —, strictures on, xvi, 51.
Compass, mariner's, on the invention of, A. Humboldt, xl, 242.
—, microscopic, J. Locke, xxiii, 237.f
—, surveyor's, improvements in, by T. Kendall, xix, 337.f
—, pivots, on the use of native alloy for, xli, 67.