Abu’l Fath `Abd al-Rahman al-Khazini

Al-Khazini was an astronomer and physician in Persia at the beginning of the 6th/12th century . Little is known about his life , other than originally he was a young Greek slave of `Ali b . Muhammad , treasurer of the court in Marw , who ensured that he received an excellent education .

His works include:

al-Zidj al mu`tabar al-sandjari al-sultani , astronomical tables based on personal observations .

Risala fi ‘l-alat , on astronomical instruments .

Kitab Muzan al-hikma , written in 515 , was a basic work on the hydrostatic balance , classifying according to the number of scales or pans . Al-Khazini’s hydrostatic balance was superior in its accuracy to all those constructed by his predecessors . Weight , according to his definition , is the force inherent in solid bodies which causes them to move , of their own accord , in a straight line towards the center of the earth and towards this centre alone; this force , in turn , depends upon the density of the body . His tables of specific weight are fairly accurate and he understood something of the influence of temperature on density .