The Hindu-Arabic Numerals c8.60

c8.60

⁴ Thus Radulph of Laon (c. 1100): "Inscribitur in ultimo ordine et figura [Figure:] sipos nomine, quae, licet numerum nullum signitet, tantum ad alia quaedam utilis, ut insequentibus declarabitur." ["Der Arithmetische Tractat des Radulph von Laon," *Abhandlungen zur Geschichte der Mathematik*, Vol. V, p. 97, from a manuscript of the thirteenth century.] Chasles (*Comptes rendus*, t. 16, 1843, pp. 1393, 1408) calls attention to the fact that Radulph did not know how to use the zero, and he doubts if the sipos was really identical with it. Radulph says: "... figuram, cui sipos nomen est [Figure:] in motum rotulae formatam nullius numeri significatione inscribi solere praediximus," and thereafter uses rotula. He uses the sipos simply as a kind of marker on the abacus.