MOHENJO-DAEO — MACKAY 441 



were probably brought by river from Sukkur, some 56 miles distant, 

 the nearest spot at which such stone is obtainable. We can imagine 

 that periodically the streets of Mohenjo-daro were " up " for the 

 cleaning and repair of the drains beneath their surface. And it is a 

 quaint commentary on the persistence of human traits that here and 

 tliere a contractor substituted a covering of brick for the more 

 valuable stone before reburying the section of drain to which he had 

 to attend. 



In three places in the city so far excavated, there are drains of 

 exceptional size and importance. They are corbel-roofed, for the 

 inhabitants of the Indus Valley in those days seem to have been 

 ignorant of the true arch, though they used wedge-shaped bricks for 

 lining their w^ells ; they were high enough for a man to walk through 

 them in a crouched position; and they had small channels in their 

 floors that look quite adequate in themselves to take the drainage 

 from buildings of ordinary size. 



One of these culverts served to drain the great tank; but as the 

 opening through which the water ran out to this drain measures not 

 more than a foot each way, so that it would easily have been carried 

 away by the channel in the floor, one is led to ask what might have 

 been the purpose of the big vaulted passage, roofed over and with a 

 manhole for someone to descend from above to clean it out. There is 

 the companion question to be answered: How was the great tank 

 filled? There is a large well in one of the eastern rooms of the 

 building, but there is no channel from it to fill the tank, nor evidence 

 of any mechanical device by which sufficient water could be supplied 

 from it. It has been suggested by Mr. Mackay that after the tank 

 was emptied the culvert was cleaned out b}^ a man who descended 

 through the manhole ; that the outflow at the far end was then closed ; 

 and that the culvert was filled up from a canal by some such means as 

 the Persian water wheel or a shaduf. If the culvert were filled to its 

 roof through a length that would bring it to the nearest point where 

 it could have reached a canal or branch of the river, the water that 

 ran back through the drain-hole into the tank would have filled the 

 latter to the depth of some 5 feet. Unfortunateh^, the culvert has 

 been destroyed at the further end, partly by the Buddhist monks in 

 the quest for brick, and partly by the hand of time. And definite 

 proof that the inhabitants of the city were possessed of so high a 

 degree of imagination and ingenuity so early in the history of man 

 is lost. 



The majority of the street drains ran into soak or sediment pits. 

 In the former, the floors of the pits were unpaved, so that the water 

 percolated away into the soil. The mud that was left was cleared out 

 by scavengers, for whose use there were footholds that still remain 



