In the north-eastern quarter, under the Corridor of the Game-Board, are still preserved some of the terra-cotta pipes which served as connections to the main drain. They are actually faucet-jointed pipes of quite modern type, each section 2-1/2 feet in length and 6 inches in diameter at the wide end, and narrowing to 4 inches at the smaller end. 'Jamming was carefully prevented by a stop-ridge that ran round the outside of each narrow end a few inches from the mouth, while the inside of the butt, or broader end, was provided with a raised collar that enabled it to bear the pressure of the next pipe's stop-ridge, and gave an extra hold for the cement that bound the two pipes together'[*] (Plate XX. 2). [Footnote *: R. M. Burrows, 'The Discoveries in Crete,' p. 9.] Indeed, the hydraulic science of the Minoan architects is altogether wonderful in the completeness with which it provided for even the smallest details. On a staircase near the east bastion, on the lower part of the slope, a stone runnel for carrying off the surface water follows the line of the steps. Lest the steepness of the gradient should allow the water to descend too rapidly and flood the pavement below, the runnel is so constructed that the water follows a series of parabolic curves, and the rapidity of its fall is thus checked by friction. The main drains are duly provided with manholes for inspection, and 'are so roomy,' says Dr. Evans, 'that two of my Cretan workmen spent days within them clearing out the accumulated earth and rubble without physical inconvenience.' Those who remember the many extant descriptions of the sanitary arrangements, or rather the want of sanitary arrangements, in such a town as the Edinburgh of the end of the eighteenth century, will best appreciate the care and forethought with which the Minoan architects, more than 3,000 years earlier, had provided for the sanitation of the great Palace of Minos (Plates XVI. 2 and XX. 1).