"You'll have three parallel lines," the Forecaster said, "the outer one longer and the next two shorter. Bisect those lines. Do you know how to do that?" The younger lad shook his head. "Only by measuring with a bit of string and doubling the string," he said. The Forecaster took a pencil and an envelope out of his pocket. "It's quite simple," he explained. "Fasten a string to the peg at one end of the line you want to divide in half. Stretch the string along the line till you come to the end of this line. Then make a circle. Do the same thing from the other end of the line. That will give you two circles crossing one another. With the board, draw a straight line joining the points where the circles cross. "To be exact, bisect the line on the middle and on the inner circles in the same way. You'll find they all come out the same. The bisecting line, reaching from the pole, and crossing the bisected lines is called the plane of the meridian. If I were you, I'd make that line a permanent mark by pressing into the ground a row of stones, or those white clay marbles. Then the rain can destroy the other whitewash lines, without doing any harm, because you've got what you were after." "But how is that going to show the time?" queried Ross. "Because," said the Forecaster with a smile, "whenever the shadow of the pole lies along the line of white marbles, which marks the meridian plane, it is exactly twelve o'clock by sun time." "Without any measuring as to length?" "Without any measuring at all." "That ain't no clock, Mistah Levin," the darky announced in a superior way. "Ah don't hold with no clock like that." "Why not, Dan'l?" "Ah gets hungry other times besides noon," he said. "Ah'd only eat once a day by that clock. No, suh, Ah wants a clock that tells every hour o' the day, not jest noon-time. "Ah got another clock that don't never need no mending, not in summer-time," continued Dan'l. "My marigolds open at seven sharp every mornin' an' wink their eyes at me an' say 'Dan'l, yo're hungry,' and Ah sho' is. An' jest before six o'clock in the evenin', the white moon-flowers say, 'Dan'l, time fo' supper and yo' little white bed.' An' dey's right, too. Don't need no sun-clocks." "I'm like Dan'l," put in Anton, "I'd like to be able to tell every hour, not just twelve o'clock only!" "Well," the Forecaster answered cheerfully, "you can make your sun-clock that way if you like." "Can we, sir?" asked Anton. "How?" "By using your pole as the style or upright of a sun-dial. Before clocks were invented, people told the time by sun-dials, and there was a whole science of sun-dials, called gnomonics. It was quite a difficult mathematical science. Even after clocks and watches came into use, sun-dials continued to be used as time-pieces, because watches and clocks were expensive and there were few mechanics who could mend them." "I've been wondering--" began Anton.