Inquiry into this feature was stimulated by a reasonable doubt concerning the reality of the immiscibility gap in the clinoenstatite-diopside series. The existence of this gap was first suspected by Sosman and Asklund, and the identity of the gap with the composition field of the hornblendes has recently been suggested by Kennedy, whose comparative study of hornblende and pyroxene composition engaged statistical methods applied in the first instance by Asklund.

As most analysts recognize, the method generally used for the determination of carbon dioxide present as carbonate, by decomposition with acid, absorption in soda-lime or soda-asbestos, and weighing as carbon dioxide, is open to several objections; and several suggestions have been made from time to time with the object of avoiding the use of absorption tubes, but none of these have come into general use, generally because of inconvenience in manipulation.

The principal objection to the use of absorption tubes (apart from their general inconvenience and the numerous precautions their use entails) lies in the uncertainty of the blank correction; when a blank experiment is performed, under precisely the same conditions as the actual determination, a small gain in weight of the absorption tubes is almost invariably observed, but in a series of several blank experiments, this gain is frequently very variable, and by no means proportional to the volume of air drawn through the absorbers, unless many precautions are observed.

In October 1875 the late J. G. Goodchild recorded his then recent discovery of a mineral which he stated 'he believed' to be wulfenite and which he had found on an old mine dump near Carrock Fell, Troutbeck, Cumberland. One specimen only was, I believe, found by Mr. Goodehild, and this he presented to the Carlisle Museum, where it has been seen by myself, the label bearing the more precise locality of Brandy Gill.

At the suggestion of Professor H. H. Read the optic axial angle and the refractive index y were measured in four hypersthenes from Aberdeenshire norites. As the values obtained suggested that the minerals were iron-rich, it was decided to have chemical analyses made. These and the optical data are set out in table I below. At the same time the literature has been searched for analyses and optical data of enstatites and hypersthenes, in order to supplement those used by A. N. Winchell in his diagram of variation of the properties of the series. The references given by Winchell have been examined, and it is found that some of the data is not reliable.

This instrument is a microscope stage-micrometer for the quantitative estimation of one to six different kinds of constituents in a substance, by the Delesse-Rosiwal method. It is intended, primarily, for linear micrometrie analysis in petrography, but has similar uses in mineralogy, chemistry, and metallography. Economic applications include the volumetric evaluation of components in building stones, road-metals, sSlid fuels, refractories, and slags.

The object of this new design is to combine speed and accuracy in operation with a particularly compact construction, mechanical simplicity, and strength. Special consideration has been given to the wear and cleansing of bearings, the definition of scale-divisions and zero-marks, and the rigidity of all supports for moving parts.

In re-examining the crystalline rocks of the Malvern Hills, the senior author has had occasion to apply quantitative spectroscopic data for the rarer constituents of hornblendes and micas. The recognition of silver in the spectrograms of biotite led to tentative fire-assays of granitic rocks in bulk-a procedure which revealed the presence also of gold.

The assay results for this preliminary suite of granitic types are given below; values less than 5 grains per ton are returned as 'traces':

The higher values appear to be related to the reddening of the felspars, which is a widespread 'late' pneumatolytic effect; it is conspicuous in the major granite masses and related pegmatites, but somewhat local and 'arterial' in its distribution over rocks of pre granite age. Among the igneous rocks of post-granite age, the intrusive granophyric quartz-diabase ('Ivy Scar' type) shows only feeble reddening; the newer dolerites are unaffected.

The natural glasses, found as small corroded pieces scattered on the earth's surface and in alluvial deposits in a few limited areas, have long presented a puzzling problem; and many theories have been propounded to explain their origin. They have been known in southern Bohemia and western Moravia since before 1787; and similar material has since been found in the Dutch East Indies, Malay States, Australia, Tasmania, French Indo-China, south China, Philippine Islands, and quite recently in the Ivory Coast in West Africa [M.A. 6-106]. These glasses are distinct in chemical composition from volcanic glass (obsidian), and there are no volcanoes in the districts where they are found. They have been given the names m oldavites, billitonites, austral ites, Darwin glass, indoch inites, rizalitcs [M.A. 4-422; 6-403], &c.

The rapid determination of the chemical elements present in a mineral has been a desideratum ever since minerals became of economic use. Various methods have been employed, starting with blowpipe work, which in the early days proved of great value, especially in experienced hands, With the development of chemistry and the discovery of new elements, this process was largely abandoned in favour of the standard ' wet method' of chemical analysis. Later on, micro-chemical reactions came into limited employment. Here the appearance of easily crystallizable salts under the microscope was used for diagnostic purposes. This method has been extensively examined of late years and became so overloaded with precautions that its chief asset, that of rapidity and case of employment, has been largely lost. Quite recently colorimetric reactions have been applied to qualitative analysis. These appeared so promising that the present author was encouraged to endeavour to apply them to the examination of minerals.

A scheme for the qualitative determination of the commoner elements was published by G. Gutzeit in 1929, which at first sight looked very attractive.

Numerous veins and veinlets of epidosite traverse the crystalline schists and associated igneous rocks of the Malvern complex. They art fine-grained, compact rocks, of uniform texture and pale greenish-yellow colour, and vary in composition from almost pure epidote to mixtures of epidote with small quantities of quartz, sphene, sericitic mica, apatite, and, in almost insignificant amount, albite.

Analytical investigation of these rocks revealed the fact that the epidote they contain holds its water more tenaciously than has hitherto been suspected : the determination of water-content by the methods usually applied to the analysis of rocks and minerals gave results which were so seriously low as to suggest that the mineral was essentially anhydrous. Though more drastic methods increased the yield considerably, they failed to liberate more than about 75 % of the amount of water which, theoretically, should be present.

The writer has recently described a small collection of glaucophane- schists from the Diahot valley and the north-east coast of New Caledonia (Jensen, 1936), and four of these contain lawsonite.

Lacroix (1897) has recorded lawsonite from New Caledonia, but the occurrence seems worthy of further mention as in two cases the lawsonite is found to be pseudomorphing plagioclase in doleritic rocks which show a relict ophitic fabric. So far as the writer is aware, such an occurrence of lawsonite pseudomorpbing felspar has not been recorded, though Lacroix figures a glaucophane-schist from Corsica which suggests this structure. The other two lawsonitebearing rocks from New Caledonia seem to have been coarse-grained plutonic rocks and probably never had an ophitic fabric.

Introduction.-There are many old records of the occurrence of chondrodite in the British Isles. Greg and Lettsom mentioned Co. Donegal in Ireland and near Loch Ness in Scotland. J.H. Collins gave Wheal Druid, Redruth, and also Scotland and Ireland. The mineral is included in a list of those associated with the kyanite of Glen Urquhart, Loch Ness, Inverness-shire, given by T. Wallace. Though reference to the Loch Ness locality is made by Dana in the 6th edition of the 'System' (1892, p. 540), the existence of chondrodite at Glen Urquhart, the only likely locality near Loch Ness, had been queried by M. F. Heddle so early as 1879. Heddle failed to find chondrodite at this locality; he gave the name xantholite to a yellowish serpentinous substance that he suggested had been hitherto mistaken for chondrodite.

Ettringite was the name given by J. Lehmann in 1874 to minute, transparent, acicular crystals lining the cavities of metamorphosed limestone-inclusions in leucite-nepheline-tephrite from the Ettringer-Bellerberg, near the village of Ettringen (between Mayen and the Laacher See), Rhineland. Lehmann detached sufficient needles from the limestone for chemical analysis, and found that they were not gypsum, as formerly supposed, but a hydrated calcium sulphoaluminate.

Available methods of grinding and polishing ore-minerals, in preparation for their examination with the ore-microscope in reflected light, fall into two categories. The more usual procedure, adapted from the corresponding methods in metallography, involves the use of high-speed laps faced with soft materials and supplied with relatively large quantities of abrasive mixed with water. The advantages of this method are its rapidity (about ten minutes will usually suffice for the whole series of processes), the possibility of using unmounted chips, and the simplicity of the necessary equipment. Amongst its chief disadvantages are the high relief developed between hard and soft minerals in the same specimen and the dirtiness of the process owing to the large amounts of wet sludge produced.

The Enoggera 'granite', in which occur the minerals to be described, is situated a few miles to the west of the city of Brisbane, and within the Greater Brisbane area. Deuteric and allied minerals have previously been recorded from quarries in the granite by H. C. Richards and W. H. Bryan, and a specimen is recorded ill the Queensland Mineral Index as 'Heulandite occurring as geodes in granite. Loc. Enoggera.'

The granite itself is very varied in character, and Bryan has recognized two main types, a pink phase and a grey phase. The pink phase approaches an adamellite, while the grey is more granodioritic in character. There is, however, every gradation from one type to the other due to admixture, and this reaches its maximum in a hybrid rock formed presumably by the mingling of the two magmas.

The meteoric stone to be described was found in 1925 by Mr. William Stewart while ploughing on his farm four-and-a-half miles south of the Morven railway station (44° 49' S., 171° 8' E.) in South Canterbury, about one hundred miles north-east of Dunedin, New Zealand. It must have weighed originally about 7100 grams, but when presented to the Otago University Museum it weighed 14lb. 14oz. (6753 grams), the remainder having been broken off by the finder. There is no local record of the fall, and the nature of the weathered crust suggests that it may have been in the soil for a long time.

The stone (fig: 1) is roughly pyramidal, measuring approximately 22.5 x 17.5 x 15.0 cm. It was covered with a thin, soft ochreous crust occasionally as much as 2-3 mm. thick.