=

all conditions of concentration and temperature only very slightly. In one experiment with cold HCl (1 part concentrated HCl 30.5 %, sp. g. 1.515 with 1 part water, time of exposition 7′), however, very small etch figures with sharp hexagonal outline were produced, not unlike those resulting from nitric acid. Their edges ran also parallel to the outer crystal edges. The absence of one set of parallel lines in the vicinity of that outer edge to which it was parallel was also observed on one crystal, etched with HCl. It is noteworthy that in this chemical process no noticeable gas bubbles are seen to escape.

Both the crystallographic measurements and the etch figures seem thus to prove the hexagonal nature of artificial domeykite crystals. On the following minerals, however: argentodomeykite, stibiodomeykite and mohawkite, the basal plane was so poorly developed that good, trustworthy etch figures could not be obtained. Their crystallographic system was deduced solely from the goniometric

measurements.

In a recent article1 on artificial domeykite crystals, Mr. Stevanovics considers the crystals examined by him to be orthorhombic, notwithstanding the hexagonal symmetry of his measurements, and bases his conclusions on the appearance of a cleavage after the macropinacoid, 100. A careful investigation by the present writer confirmed the cleavage noted above after three faces 60° apart. The cleavage seemed equally good after all three faces. In certain pieces cleavage fragments of perfect hexagonal outline (equilateral triangles) were produced. On the goniometer the angle between two such cleavage faces was found to be approximately 60°. The basal plane was uneven and did not permit an exact adjustment of the crystal.

The elements and forms described by Mr. Stevanovics were the following:

with t, r, q rare and uncertain.

As hexagonal crystals these elements and forms become :

1 Zeitschr. f. Krystallographie, Vol. xxxvii, pp. 245-246, 1903.

The crystals of the artificial argentodomeykite belong also to the holohedral division of the hexagonal system. Four crystals only were measured, each crystal exhibiting slightly different elements, due probably to a varying percentage of silver. For the form p, 20 of the several crystals

Although the above quantities vary considerably, still they show clearly that the entrance of the silver in the domeykite crystal particle causes a change in its elements, the pyramids becoming steeper.

Fig. 6.

The quality of the faces of these artificial crystals was so poor that the influence of the silver in per cent. could not be determined.

Size of crystals and character of faces similar to domeykite. Of the pyramids the form p, 20 predominates, the form v, 10 occurred but once, while p, o was not observed. The face p, 20 frequently exhibits a slight cylindrical rounding, the axis of which runs parallel to the basal edge. Its reflexion signal is then a short light band, its bright central part indicating the position of the face. The faces are invariably striated horizontally. The different types of

crystal habit are illustrated in Figs. 6 and 7 (dimensions of crystals 0.9 × 0.9 × 0.4 mm. and 1 x 0.5 X 0.4 mm.).

The external appearance of the artificial argentodomeykite resembles that of domeykite. Its color is perhaps more nearly silverwhite. The crystals tarnish easily and become iridescent.

STIBIODOMEYKITE.

The artificial products of this mineral were not suitable for goniometric measurement. The faces were without exception uneven. An examination of the various preparations with a pocket lens revealed two different types of crystal habit—the first of them tabular with the base predominating, the other faces practically undeveloped ; the second long prismatic, almost arrow-shaped, the horizontally striated pyramid faces terminating either in a short point

Fig. 7.

or becoming wider at the top, and resembling then an overturned bottle or inverted cone.

Color, light steel-gray. Tarnishes less readily than preceding minerals and iridescence rarely noticeable. Fracture conchoidal. H=3-4.

PROC. AMER. PHILOS. SOC. XLII. 173. q. PRINTED AUG. 7, 1903.

MOHAWKITE.

The artificial crystals of mohawkite are extremely small, and not so well developed as those of the domeykite. On the goniometer their faces exhibit unclear, manifold reflexion signals which render an exact determination of the element impossible. The measurements indicated again the holohedral division of the hexagonal system.

The element was computed from the mean of all usable angles. Possibie error ± 14'. The marked variation in the angles was due to the poor quality of the crystal faces. A careful search through the entire material showed that not one of the faces was perfectly The dimensions of the crystals are so small that the observer is unable to judge, even with the aid of a pocket lens, accurately as to the quality of the faces. The individual forms exhibit a sharp outline but an uneven, rolling surface. On the goniometer, afterwards, these characteristics are only too noticeable.

even.

Table of Angles.

1001| (G.

C1'501 lg c-017656 lg a―006247 lg Po=000043 a0=1'154 Po=1'00

The general character and relation of the faces on the mohawkite crystals is similar to that of domeykite. The form a, 0.00 ∞ (1120), however, occurs more frequently and is better developed. Fig. 8 (size of crystal 0.6 X 0.3 mm.) illustrates the usual habit of the

mohawkite crystals. Thin, tabular crystals like those of Fig. 2 are

rare.

Luster, splendent metallic. Color, light tin-white to steel gray. Fracture conchoidal, crystal habit thick tabular to equidimensional. The crystals tarnish more readily than those of domeykite and become iridescent in brilliant, variegated hues.

LANGUAGES OF THE NEW ENGLAND ABORIGINES

NEW SOUTH

WALES.

BY R. H. MATHEWS, L.S.,

ASSOCIÉ ÉTRANGer soc. d'anthROP. DE PARIS.

(Read May 15, 1903.)

SYNOPSIS.-Introductory-Orthography-The Anewan Language -The Banbai Language-A Mystic Language-Anéwan Vocabulary.

The native tribes of New South Wales are disappearing rapidly before the advancing tide of European population, and unless some 1 See foot-note, page 243.