INTRODUCTION. THE bekhaganita: its oontents. • The Rekhaganita or the Science of Qeometry is a Sanskrit version of Euclid's Elements of Geometry by Samr&t Jagann&- tha under the orders of Jayasiffiha, king of Jeypore. It con- tains fifteen 'adh;&yas' or books. The first four and the sixth books are devoted to plane geometry and the fifth deals with the laws of proportion which are utilized in the sixth book. The contents of these books are well-known and therefore need no detailed account. The seventh^ eighth, and ninth books are purely arithmetical. As the subject-matter of the tenth book which treats of incommensurable quantities and of the eleventh and the succeeding books which are concerned with solid geometry cannot be dear unless the theory of numbers is ex- plained, the intermediate three books, the seventh, eighth, and ninth, are devoted to the elucidation of the principles of numbers. A number ( nr ) is defined as a multitude com- posed of units (j^y Numbers are divided into even (jm) ^^^ <^d ( fi^nf ). Even numbers are subdivided into evenly-even (fTH^nr) Ai^d evenly-odd (f|i|ftM4<) » Evenly^even numbers are those which, when divided by an even number, have an even quotient, as 8. Evenly-odd numbers are those which, on being divided by an even number, give an odd quotient^ as 6. Odd numbers may be oddly-odd (ft ^ ii|fi|f|4j) , when they have an odd quotient, on being divided by an odd number, as 9. Numbers are further divided into prime numbers ( snnvnF )} and compo- site numbers (irinilF)^ and into commensurable (ftr%9}> and incommensurable ( f^ ). A number produced by the product of two numbers, the multiplier (ipiv) &nd the mul- tiplicand (g«i|), is a plane or superficial number ( jhre^), the two numbers ( jpnf and ijmip ) being called its sides or arms ( ^ )• A superficial number, multiplied by a number, becomes a cube number (^pn;^). The product of a number by itself is a square number ( W^Aff )> and a number, multi- plied by its square^ becomes a cube number (9«n|F)* Numbers
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