Under Castillian rule, the Palace of Galiana became the property of the Guzmans, whose arms may be seen upon its dismantled front, and who, like most Spaniards, have so ill appreciated a priceless inheritance. One of the most famous attractions of this palace in olden times was the _clepsydras_, or water-clocks, made by the celebrated astronomer, Abou-l'-Casem, Abdo-er-Rahman, better known as Az-Zarcal. In a description of Toledo a curious Arabian document gives us a quaintly vague idea of these clepsydras, or ponds, whose waters rose and fell with the moon. "One of the greatest towns of Spain is Toledo, and Toledo is a large and well-populated city. On all sides it is washed by a splendid river called the Tagus.... Among the rare and notable things of Toledo is that wheat may be kept more than seventy years without rotting, which is a great advantage, as all the land abounds in grain and seed of all kinds. But what is still more marvellous and surprising in Toledo, and what we believe no other inhabited town of all the world has anything to equal, are some clepsydras or water-clocks. It is said that Az-Zarcal, hearing of a certain talisman, which is in the city of Arin, of Eastern India, and which Masudi says shows the hours by means of _aspas_ or hands, from the time the sun rises till it sets, determined to fabricate an artifice by means of which people could know the hour of day or night, and calculate the day of the moon. He made two great ponds in a house on the bank of the Tagus, not far from the gate of the tanners, making them so that they should be filled with water or emptied according to the rise and fall of the moon." We are told that the movements of these clepsydras were thus regulated, that as soon as the moon became visible by means of invisible conducts, the waters began to flow into the ponds, and by day-rise the ponds were filled four-sevenths. At night another seventh was added, so that by day or night the ponds continued to increase in water a seventh every twenty-four hours, and were quite full by the time the moon was full. On the 14th of the month, when the moon began to fall, the ponds fell too in like proportion. On the 21st of the month they were half empty, and on the 29th completely so. King Alfonso the Learned, desiring to master the secret of these clepsydras, sent one of his bungling astronomers to examine them, which he did so well, that he broke the delicate machinery, and the Moors, to comfort their wounded pride in the loss of so unique a Moorish monument, called the bungler a Jew, one Houayn-Ben-Rabia.