The loxodromic charts first appeared in Italy, and were so called from the fact that they were crossed by loxodromes (or rhumb lines) radiating from a number of crossing points distributed regularly over the map. Compass roses carefully drawn were later added at these crossing points, the first appearing on a chart of 1375. The earliest known mention of the variation of the compass from true north was on the first voyage of Columbus, who discovered this important fact in 1492, and as a consequence his "seamen were terrified and dismayed." Before that time it was assumed in Europe that the compass pointed "true to the north pole." The apparent failure to detect the variation earlier was doubtless to some extent due to its small amount at that time along the Mediterranean. The earlier charts showed both lines and compass roses apparently oriented with the true meridian, though there is some evidence to indicate that they were actually oriented with the magnetic meridian, the designer not recognizing any difference. The variation of the compass was first marked on a map in 1532 and on a printed chart in 1595, but the placing of magnetic compasses on charts did not become customary until about fifty years ago. These early charts were drawn on parchment, using bright colors. They were copied by hand, one from another, with gradual variations. They had no projections, and the draftsmen evidently had no idea of the sphericity of the earth. Islands and points were usually exaggerated; shallows were indicated, but no soundings; no information was given as to the interior of the countries; a scale of distances was nearly always provided. Charts were first printed about 1477, and are known to have been engraved on copper by 1560. The maps of Ptolemy were ruled with degree lines, but no chart was so provided until 1427; by 1500, however, most charts were graduated. Before this date it is not known on what projection the charts were constructed. On the first graduated charts the degree lines were equidistant parallel straight lines cutting each other at right angles and thus dividing the chart into equal squares or rectangles. These were known as "plain charts." This square projection had little to commend it save simplicity of construction, as in higher latitudes it gave neither directions nor distances correctly. The difficulties of its use in navigation were early recognized, and nautical works contained chapters on "sailing by the plain chart, and the uncertainties thereof." The example of early chart making shown in Fig. 2 is of great interest as being the earliest extant chart which includes America. This chart was drawn on ox-hide in 1500 by Juan de la Cosa, who accompanied Columbus on his first voyage as master of his flagship, and on his second voyage as cartographer. The chart, of which only a portion is shown here, purports to cover the entire world; it joins Asia and America as one continent, the Pacific Ocean being then still unknown.