This night I suffered for two hours from colic, and I fancied I felt the movement of a stone. Early on Thursday morning I went to see one Guglielmo Felix, a Jewish doctor, who talked to me some time as to my general rule of living with regard to my kidneys and the gravel. I then left Siena, and was again troubled with colic for three or four hours. Then the pain came to a crisis, and I was assured that a stone must have passed. We travelled twenty-eight miles and supped at Ponteaelce,[112] where I passed a stone bigger than a grain of millet, with a quantity of red gravel, but I suffered no pain. We left on the Friday morning, and halted sixteen miles along the road at Altopascio, where we stopped an hour to feed our cattle. On the road we saw divers peasants gathering up the vine leaves, which they keep to use as fodder during the winter; others were collecting ferns wherewith to feed their cows. We slept at Lucca, eight miles farther on, and there divers gentle-folk and craftsmen came to visit me. On Saturday, October 21st, after having eaten a bunch of grapes (in these travels of mine I have eaten fruit sparingly or not at all in the morning), I set forth without waiting for certain gentlemen who had made plans to accompany me. We travelled over a good road, for the most part level; on the right hand the mountains, thick set with olive trees, and on the left the marshes, with the sea beyond. At a certain spot in the dominion of Lucca I came upon an engineering work which has partially fallen into ruin through the neglect of the government, a neglect which has been the cause of great loss to the country round. This was a construction devised to drain and render fertile the marshes aforesaid. In the first place, a deep ditch was dug through the marshes, at the end of which were fixed three wheels, kept in motion by a stream of running water brought down from the mountains so as to fall upon them. To these wheels were attached a number of buckets in such fashion that they took up water from the ditch on one side and threw it over on the other side of the bank into another channel on a higher level. This last-named channel, cut for the purpose and lined with bricks throughout, conveyed the water to the sea, and thus drained all the country round.[113]