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 Palaeozoic Calamarieae, though so far surpassing recent Equisetaceae, both in stature and complexity of organization, clearly belonged to the same class of Vascular Cryptogams. There is no satisfactory evidence for attributing Phanerogamic e **bn** FIG.

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", ..