Page:Journal of a Voyage to Greenland, in the Year 1821.djvu/207

This page has been validated.
155
voyage to greenland.

an instrument called a magnitimeter, invented by him for measuring magnetic attraction, and finding the dip of the needle: some extremely curious experiments were likewise made on the magnetic laws relative to the production, and annihilation of magnetism in iron, by percussion; and on a recent discovery of the precise effect on iron bars, becoming magnetical by position. It is certainly one of the most ingenious instruments I ever saw, and its utility was clearly proved to me in repeated experiments, which, in the science of navigation, must be pre-eminently important. The combined attraction of the iron in the ship, influencing the compass placed near it, was determined also in the most satisfactory manner by comparing the polarity of the compass in the crow's nest, with that in the binnacle, or place where the compass is kept on the ship's deck.

There being but very little wind, I went in pursuit of unicorns, and to shoot aquatic birds; and I succeeded in procuring some good specimens. On my return to the ship, my attention was called by Captain Scoresby to an extraordinary instance of refraction; it was visible to the naked eye, but with a telescope the effect produced by it was astonishing: the atmosphere was particularly clear, the sun extremely bright, and a gentle breeze blowing from the south-west, when, on looking over the western horizon, there appeared to ascend from the distant surface of the ocean, a perpendicular cliff, as if formed of the most regular basaltes of several