Little Masterpieces of Science: Explorers

What was thought possible by the early navigators possessed the minds of all seamen in varying experiments for two centuries and a half. Though not reaching such satisfactory results as were hoped for, the expectation did not prove so chimerical as was sometimes imagined when it was discovered that the lines of variation were neither parallel, nor straight, nor constant. The line of no variation which Columbus found near the Azores had moved westward with erratic inclinations, until to-day it is not far from a straight line from Carolina to Guinea. Science, beginning with its crude efforts at the hands of Alonzo de Santa Cruz, in 1530, has so mapped the surface of the globe with observations of its multifarious freaks of variation, and the changes are so slow, that a magnetic chart is not a bad gu