Friern Barnet adjoins Finchley on the north and **Whetstone** on the south, the whole district being residential.

Robert Recorde in his **Whetstone** of Witte (1557) uses the variant algeber, while John Dee (1527-1608) affirms that algiebar, and not algebra, is the correct form, and appeals to the authority of the Arabian Avicenna.

The first treatise on algebra written in English was by Robert Recorde, who published his arithmetic in 1552, and his algebra entitled The **Whetstone** of Witte, which is the second part of Arithmetik, in 1557.

When the latter desired to double the number of the equestrian centuries, Navius opposed him, declaring that it must not be done unless the omens were propitious, and, as a proof of his powers of divination, cut through a **whetstone** with a razor.

Navius's statue with veiled head was afterwards shown in the comitium; the **whetstone** and razor were buried in the same place, and a puteal placed over them.

Bothe for the use of Instrumentes Geometricall and Astronomicall, and also for Projection of Plattes (London, 1551); The Castle of Knowledge, containing the Explication of the Sphere both Celestiall and Materiall, &c. (London, 1556); The **Whetstone** of Witte, which is the second part of Arithmetike, containing the Extraction of Rootes, the Cossike Practice, with the Rules of Equation, and the Woorkes of Surde Numbers (London, 1557).

"Ozheg-zheg, Ozheg-zheg..." hissed the saber against the **whetstone**, and suddenly Petya heard an harmonious orchestra playing some unknown, sweetly solemn hymn.