Boron nitride **BN** is formed when boron is burned either in air or in nitrogen, but can be obtained more readily by heating to redness in a platinum crucible a mixture of one part of anhydrous borax with two parts of dry ammonium chloride.

**Bn** a p.

If **BN**, CP, DQ, FS, GT are the perpen diculars to AE from the angular points, the ordinates NB, PC,..

Between 1895 and 1906 they rose 15% **bn** the average among males of all ages, and as much as 30% among women and girl workers.

If bl, b2, ..., k J is the cycle of recurring quotients, then b n 2a1, b, bn_1, b 2 bn_2, b 3 = bn_3, &c.

**Bn**, from which n - n 1 I n b2b3.

3 **bn** con - a 2 -a3 -.

Determinant a1 - I a2 O -I o 0 u an **bn** O O - - o o -I a n, from which point of view continuants have been treated by W.

The second and third terms each vanishing, it is a, b, c a', c', , a", **bn** c",, But if the linear equations hold good, then the first column of the 1 The expression, a linear function, is here used in its narrowest sense, a linear function without constant term; what is meant is that the determinant is in regard to the elements a, a', a", ..