The mineral schwartzembergito was first described by Domeyko in 1864 as an oxychloroiodide of lead from the Desert of Atacama. The specimens, which are said to have been collected about ten leagues from Paposo in the Desert of Atacama, at a mine worked for argentiferous galena, were brought to his notice by Dr. Schwartzemberg, an assayer at Copiapo, who had recognized the material as being an iodide of lead. Domeyko made a chemical analysis (see p. 82) of the mineral, a yellowish crust, 1 to 2 mm. in thickness, upon galena, and obtained the formula, 2Pb(CI,I)2.3PbO, the specific gravity being 5.7; no crystal measurements were obtainable, neither were any optical observations made.

Analyses of Indian manganese-ores generally show the presence of small amounts of arsenic. The form in which this constituent occurs was discovered by Dr. L. Leigh Fermor in the course of his investigations of these well-known deposits. At two different localities crystalline arsenates were found. One of these occurrences is at the Sitapar deposit in the Chhindwara district, Central Provinces. The pinkish-white to white arsenate found there is the new mineral to which we have given the name fermorite. The other locality at which an arsenate was found is Kajlidongri, Jhabua State, Central India. The pale-green arsenate, somewhat resembling apatite in appearance, which occurs at this locality has been found by us to be identical with the tilasite from Sweden described by Sjögren.

In the course of an investigation of the atomic weight of nitrogen Mr. F. P. Burt, of University College, London, prepared by the following process crystals of nitrogen sulphide, N4S4, surpassing in purity any that had been previously obtained. The nitrogen sulphide was recrystallized from benzene, washed with carbon disulphide to remove as much sulphur as possible, and finally washed with a little cold benzene. The product was powdered on a porous tile, and kept in a desiccator with calcium chloride and cocoa-nut charcoal until it no longer smelt of benzene. It was then sublimed in vacuo over silver gauze heated to 100° C. in a steam-jacket, by which means the absence of liquid or gaseous inclusions and of free sulphur in the sublimate was assured.

The instrument to be described in the following pages is a goniometer of the suspended type. It is intended primarily for tlle examination of small crystals, and by its aid all the usual crystallographic and optical determinations can be readily carried out. In its design the attempt has been made to combine efficiency with simplicity and strength of construction, together with adaptability to very various purposes. The instrument was completed in the spring of 1899, and has been in continuous use in the Mineralogical Laboratory at Cambridge ever since. Other instruments of the same general type were in existence at the time, or have been described during the past twelve years, and several features which were novelties when it was first constructed can no longer lay claim to originality.

In a previous number of the Mineralogical Magazine (1909, vol. xv, p. 260), attention was called to a simple electrostatic method whereby, using a stick of sealing-wax and a copper plate, grains of minerals which have a metallic or sub-metallic lustre can generally be separated from those of the more transparent minerals, the former being attracted notwithstanding the fact that they are usually heavier than the latter.

Examples of quartz twinned on a face of the primary rhombohedron R are extremely rare. Only three isolated examples have so far been recorded. The first was observed by Q. Sella; but as his crystal could not be measured, owing to its position on the matrix, it is of only slight importance as evidence of this mode of twinning of quartz.

The following notes on some peculiar forms of cassiterite found in the Malay Peninsula will, it is hoped, prove of interest and an addition to our knowledge of the mineral.

It is now well known that the most effective method of separating wolframite from eassiterite on a commercial scale is the electromagnetic process, which, in theory, lifts all the wolframite from the ore and lèaves a concentrate of cassiterite. In practice, however, the separation is rarely, if ever, perfect; and it has been possible for the writer to obtain some interesting information bearing on the point, the most valuable being the discovery of a few specimens of cassiterite that may be termed magnetic in that it can be lifted by an electromagnet.

At the Society's Anniversary Meeting of November, 1908, I exhibited and gave an account of an unnamed crystal from the dolomite of the Leugenbach quarry in the Binnenthal, Switzerland. In the notice of this meeting, as given in ‘Nature’ of December 10, 1908 (vol. lxix, p. 142), this mineral, which could not be identified with any of the sulpharsenites of lead previously described, is referred to as follows :— ‘One of these [black minerals with metallic lustre] is oblique with β = 81° 11′, (100),(101)= 40° 7′, (010),(111) = 5° 26′; it has a perfect cleavage (100), and, like liveingite, exhibits no oblique striations on the planes in the zone [100,001].’ Owing to lack of material, the chemical composition and specific gravity of this apparently new mineral could not be determined.

Examination of a series of examples of vein-breccias demonstrates that while many have readily explicable characters in common, others differ from ordinary types, and exhibit peculiarities calling for special investigation.

Professor H. Louis, of Armstrong College, handed over to me for examination some crystals of gypsum which had been sent to him by Mr. Frank E. Lott, A.R.S.M., F.I.C., of Burton-on-Trent. Mr. Lott has kindly furnished me with the following particulars.

The crystals were deposited in an apparatus employed for raising steam in the production of distilled water. This apparatus consists of a copper vessel enclosing steel steam pipes for heating the water. The crystals were deposited on the walls of the copper vessel and on the steel pipes, and had been formed within a period of twelve months.

The inquiry that I have recently made into the weight of the ‘Cullinau’ diamond has led me to clear up, as far as possible, various discrepancies in the published statements respecting the other large diamonds of South Africa. Although a knowledge of the exact weights of these stones is a matter of only trivial scientific importance, yet it is desirable to place on record any definite facts that may still be gathered respecting them. Much valuable information in this direction has been freely given to me by Messrs. Wernher, Beit & Co., through whose hands several of the larger stones have passed ; without their help the present notes could not have been written, and I therefore desire to express to them my hearty thanks.