This article focuses upon three main concerns. The first is an overview of the textual tradition of a central part of Arabic mechanics dealing with the science of weights. A short paragraph on the ongoing digitization of Arabic mechanical writings is appended to this description of texts in order to indicate how they are being analyzed with the new tools of information technology. This is followed by an assessment of the historical significance of the Arabic science of weights, in which the transformation brought about in this important sub-field of Arabic mechanics is interpreted as the reorganization of a core part of ancient mechanics into an independent science of weights. Upon this basis, a strong claim is made in favour of the independent status of ʿilm al-athqāl, which may no longer be confused with ʿilm al-ḥiyal, understood as a general descriptive discourse upon different types of machines. Finally, the paper presents a preliminary survey of the institutional setting for the control of weighing instruments in Islamic medieval society through the office of ḥisba.‬