In a previous paper the author pointed out the advantages of a goniometer possessing three graduated circles, and described an instrument of this type which had resulted from the addition of a two-circle arrangement to an ordinary reflective goniometer with a single (horizontal) circle. As was remarked in that paper, the adapted instrument has unavoidably the disadvantage that measurements can be made through little more than a right angle in any particular zone, with the single exception of the zone of reference, without readjustment of the vertical and third circles. The zone may, indeed, be completed by measuring from the diametrically opposite pole in the zone of reference; but difficulties occasionally arise in practice, and it is convenient to be able to measure through at least two right angles round the free end of the crystal by rotation of the horizontal circle only.

Anatase.—Some very brilliant and highly modified crystals of a light brown colour were obtained from the Ofenhorn in 1908. The largest crystal measures nearly an inch across. The. form {313} is largely developed; other forms present are {100}, {110}, {111}, {331}, {221}, {223}, {835}, {112}, {118}, {117},and also a new {h k l} plane close to (110) and (221), which is probably (24.14.7). These crystals resemble Seligmann's fig. 3.

In 1902 some much smaller, dark brown crystals of a different habit, with the form {117} largely developed, were obtained from another part of the Ofenhorn. They resemble Klein's fig. 3. Three new forms were observed, namely {553}, {35.8.5}, and {40.3.5}.

Mr. G. F. Herbert Smith has pointed out the advantages of the gnomonic projection for some special crystallographic problems. It seems to me that much of the labour in drawing the projections could be saved by a device similar to that employed by Fedorow, Wulff, Penfield, &c., in drawing stereographic projections.

Corresponding to the ‘stereographic net’ described by these authors (which is the stereographic projection of lines of latitude and longitude on a plane through a llne of longitude), we have the gnomonic net, which is the projection of the lines of latitude (l) and of longitude (m) on the tangent plane at the point whose latitude and longitude are zero. The lines m are parallel straight lines, the lines l are hyperbolae having double contact with each other at two fixed imaginary points.

Amongst the specimens recently selected for the British Museum from the collection of South American minerals brought together by the late Theodor Hohmann, are two on which occurs a mineral in thin laminae resembling graphite. From the locality and associations, the mineral was at first presumed to be either franckeite or cylindrite, the two sulphantimonite-sulphostannates of lead from Bolivia, which were described in 1893 by Stelzner and Frenzel respectively. Qualitative analysis, however, soon showed that, although similar to them in physical characters, it differed chemically from both franckeite and cylindrite in containing no antimony, but only lead, tin, and sulphur.

Of the two specimens from the Hohmann collection, one was labelled ‘sulphoselenide of lead from Bolivia,’ and the other ‘selenide of lead from Atacama,’ so that unfortunately the precise locality of the mineral is at present unknown. In all probability both specimens came from the same district in Bolivla, since in appearance they are very similar.

In November, 1836, Captain (afterwards Sir) James Edward Alexander was at Henkrees (29° S., 18° E.) on the southern side of the Orange River, South-West Africa, and sought for information as to what he might expect to find during his intended journey across Great Namaqualand. He says :—

‘A respectable old Bastaard lived at Henkrees, Balli by name; he was the owner of a thousand head of cattle, of many horses and sheep. … He also told me of great quantities of copper far up the Great Fish River, and of hills from which malleable iron could be cut out.

A small specimen (weighing 20 grams), with a label carrying the inscription ‘Meteoric Iron from the banks of the Great Fish River, South Africa,’ was included in a mineral collection presented to the British Museum in 1878 by Mr. Benjamin Bright, of Bristol; the collection had been begun by Mr. Richard Bright (1754-1840), and increased by his son, Mr. Benjamin Heywood Bright (1787-1843), father of the donor. No lists or letters were handed over with the collection, and the history of the specimen and its label, prior to 1878, was thus unknown : as no additions to the collection seem to have been made by Mr. Benjamin Bright himself, the Great Fish River specimen had probably been acquired not later than 1848, the year in which his father had died.

The mass of meteoric iron brought Dora Patagonia in 1896 by Dr. Francisco P. Moreno, Founder and Director of the State Museum of La Plata, had been sought for by him, while exploring that region, because of a reference which had been made to it in Captain G. C. Musters's book, ‘At Home with the Patagonians,’ published in 1871.

Dr. Moreno believed the mass to be really identical with a block of supposed marble, referred to on page 87 of that work as having been seen by Captain Musters in 1869 at Amakaken, which is situated in longitude 71° 56′ W. and latitude 48° 10′ S.

Some small isolated crystals from the gem-washings in Ceylon, recently sent by Mr. A. K. Coomáraswámy to the British Museum for determination and study, were at first thought to be rutile, but on detailed examination proved to be zircon of a rather unusual type. This has a specific gravity of 4.0, which is not increased when the crystals are heated.

The majority of the crystals are from the Balangoda district in the Sabaragamuwa province, and, according to Mr. Coomáraswámy have been derived from a group of zircon-granites which occur in this district; a few others are from Walaweduwa in the Bamberabotnwa district, and from the Hatton district. Associated with them are zircons of more usual types (see p. 48); the present description is, however, confined to the crystals of lower specific gravity.

The diagram (Plate III), to which for convenience the author has given the name moriogram, is intended to provide a method for rapidly determining the angles between a face of symmetry and all other faces with rational indices, which lie with it in some particular zone, when two of the angles are known, or, what is precisely the same thing, between a zone of symmetry and all other zones with rational indices, which intersect it in the same pair of opposite poles, when two of the angles are known : whenever possible it should be arranged that one of the known angles is a right angle. The meriogram may, therefore, be used in the course of computation for checking the accuracy of the work, or during the goniometrical measurement of a crystal for finding the relations subsisting between the faces or the zones.

Some months ago Professor Henry Louis presented to this college several isolated crystals which he had brought from the Sulitjelma (or Sulitelma) mines in Arctic Norway: they occur there in masses of copper-pyrites and iron-pyrites, for which this district has been famed for some years.

The crystals are of various sizes, ranging in length from 4 to 8 mm. They have a metallic lustre and silver-white colour. The fracture is uneven, and no cleavage is visible. On a freshly broken surface small yellow particles can be seen with the naked eye; these also have a metallic lustre, and are probably iron-pyrites, a probability which is strengthened by the appended chemical analysis. The specific gravity varies from 5.94 to 6.02, and the hardness is just under 5. The crystals are all of a pronounced rhombic aspect.