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gems, and his information is quite precise and accurate as can be seen from the contemporary Arabic works on gemmology. 14
Though the Ratnaparikṣā cannot be counted among Pheru's best works, it exemplifies certain characteristics of Pheru as a writer. These characteristics are as follows; (i) Where there exists a corpus of traditional literature on a subject, he is content to follow the traditional framework and to present the material in Prakrit (as in the description of gems). (ii) However, he makes innovations in the traditional framework if practical considerations demand them (e.g. the price tariff ; see also 2.4 below). (iii) But where there is no traditional literature to lean on, he writes from his practical knowledge, and is most original and precise (e.g. on the gems imported from Persia). The Dhātut patti
ee 25) and more particularly the Dravyaparik şā (see 2.6) belong to this category of original works.
2.4 The Ganitasāra on arithmetic is not dated but must have been written before 1318. Compared to the previous text, this one is more innovative, not so much in the theoretical portions but in the application of arithmetical rules to a wide range of areas. It is commonplace to say that arithmetic is one of the most practical of sciences, its rules being employed by traders, masons, carpenters, tax-collectors and the like for the calculations connected with their professions. The units of measurement and the examples to illustrate arithmetical rules given by Pheru throw a flood of light on the economic and social conditions of this period. Here a few examples will suffice.
In the section on solid geometry, Pheru gives the rules for the volumes of domes (gonamța), square and circular towers with spiral stairways in the middle (pāyaseva), towers with fluted columns (munāraya), niches (tāka), staircases (sopāna), bridges (pulabamdha) and so on (III. 74-86). It should be noted that some of these are new architectural features being introduced by the Muslim rulers in India in this period. The purpose of such rules is to enable the chief mason to calculate the number of bricks or stones needed for these constructions. To do this calculation more exactly, Pheru informs us, one should first calculate the total volume of the wall-space, subtract from this the volume of the space occupied by the doors and windows and reduce the remainder by threetwentieths, the latter being the volume of the
14 Cf. Eilhard Wiedemann, Aufsaet ze zur arabischen Wissenschaftsgeschichte, hrgg.
Wolfdietrich Fischer, Hildesheim, New York, Vol. I, pp. 835-53.
152, JAINTHOLOGY
