A semicircle is then drawn behind the bowls with a radius of 9 ft.
Three points are given to the bowl that trails the jack over both lines into the semicircle and goes over them itself.
Let APB be a semicircle, BT the tangent at B, and APT a line cutting the circle in and BT at T; take a point Q on AT so that AQ always equals PT; then the locus of Q is the cissoid.
Four conspicuous features of Pyrenean scenery are the absence of great lakes, such as fill the lateral valleys of the Alps; the rarity and great elevation of passes; the large number of the mountain torrents locally called gaves, which often form lofty waterfalls, surpassed in Europe only by those of Scandinavia; and the frequency with which the upper end of a valley assumes the form of a semicircle of precipitous cliffs, locally called a cirque.
The main water-parting of the Peninsula is everywhere near the edge of the table-land on the north, east and south, and hence describes a semicircle with the convexity to the east.