text:  The famous fountain of quicksilver which could be set in motion at pleasure was placed in the _Kasr-al-Kholaifa_ or hall of the khalifs "the roof and walls of which were of gold and solid but transparent blocks of marble of various colours: on each side were eight doors fixed on arches of ivory and ebony ornamented with gold and precious stones and resting on pillars of variegated marble and transparent crystal:--and in the centre was fixed the unique pearl presented to An-nassir by the Greek Emperor