Friern Barnet adjoins Finchley on the north and Whetstone on the south, the whole district being residential.
The outer cuticle of Oriental species is so hard that it forms a sharp and durable cutting edge, and it is so siliceous that it can be used as a whetstone.
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.