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Author: Yousef Yassi

The water clocks of the 12th-century Islamic scientist Ismail Al-Jazari may be regarded as among the most outstanding engineering masterpieces in the history of science and technology in Persia. His other works testify to his remarkable ability in design methodology and in different aspects of mechanical engineering design and manufacture such as robotics, fluid mechanics, strength of materials, and statics. In this study in experimental archaeology two of his water clocks – namely the dragon clock and the peacock clock – were considered for the purposes of making working reconstructions. The historical background, design details, and a technical and comparative analysis of these inventions are presented here. Replicas were constructed in accordance with the indications provided in Al-Jazari’s A Compendium on the Theory and Practice of the Mechanical Arts and tests have shown that both clocks operated exactly as described in his book, and with an acceptable degree of precision.

In: Nuncius
Author: Yousef Yassi

After the advent of Islam the interest of scientists was drawn towards “ingenious devices.” Ahmad ibn Müsä ibn Shäkir Khuräsäni was one of the greatest Iranian scientists of the 9th century AD. He worked on many mechanical, hydraulic and pneumatic devices and presented his inventions in a book entitled Kitäb Al-Hiyal. A combined historical and experimental research project was undertaken by the Iranian Research Organization for Science and Technology (IROST). One part of the project consisted of designing and reproducing the mechanisms for separating liquids described in Al-Hiyal. This paper provides details of the design of four of these devices, which function on the basis of the relative viscosities or densities of the liquids being separated. They were recreated and tested in accordance with the indications provided in ibn Shäkir Khuräsäni’s text. This paper provides the historical background and a technical analysis of these remarkable inventions.

In: Nuncius
Authors: Yousef Yassi and Reza Yassi

Abstract

Abu al-Fath Khazini’s “Balance of Wisdom” was one of the most sophisticated and advanced balances to be designed and manufactured in the medieval Islamic world. Hydrostatic balances were used to assess the value of the precious metals and gemstones entering the royal treasury. Al-Khazini presents a detailed description of his balance in Al-Kitab Mizan Al-Hikma. Among the advantages of this instrument were its higher degree of precision, its complex triple action, and its ability to identify and determine the percentage by weight of the constituent elements in a binary alloy, provided one of the elements in the alloy is known. It was also capable of measuring the weight and density of pure metals and alloys with a high degree of accuracy. This paper describes the construction of a prototype of Al-Khazini’s balance and the testing of its accuracy in weighing, titration, and the identification of elements following the instructions contained in Al-Kitab Mizan Al-Hikma. The instrument was found to function as accurately as claimed by its inventor.

In: Nuncius