The object of this note is to place on record an interesting occurrence of vanadiferous nodules on the coast of South Devon. I have to thank Lord Clinton, the owner of the property on which the nodules occur, for the assistance and encouragement he has given me in this matter, and Lieut.-General Sir William Furse, the Director of the Imperial Institute, for kindly arranging to have chemical analyses carried out by Miss Hilda Bennett in the Institute Laboratory. I also have to thank Mr. Thomas Crook, of the Imperial Institute, for the trouble he has taken to write up this short paper on the basis of my notes and the laboratory work done at the Institute.

The discovery of tin-ore in Ankole (south-western Uganda) led to a great deal of prospecting on the part of qualified and unqualified, experienced and inexperienced, individuals, not only in the vicinity of the original discoveries, but also in many other parts of the Protectorate. One of the results of this activity was the finding, by a prospector, of a deposit of alleged coal at a spot rather less than 25 miles WNW. (approx.) of Kampala and about 35 miles NW. of Entebbe. With reference to this, the discoverer was told by the Geological Survey that his hoped-for fuel was in reality tourmaline, but inasmuch as it was associated with a pinkish-buff mica characteristic of the stanniferous pegmatites of Ankole, further search might disclose the presence of tinstone.

In a brief account of the Johnston-Lavis collection of Vesuvian minerals, now preserved in University College, London, Dr. K. W. Earle mentions ‘a large number of specimens of “Thermokalite”, a new member of the Haloid group, which has, apparently, so far escaped description.’ This previously unpublished name was copied from Dr. Johnston-Lavis's manuscript labels. The late Dr. H. J. Johnston-Lavis (1856-1914) possibly considered that this mineral was the potassium compound corresponding to thermonatrite [Na2CO3.H2O]. A provisional name for an undetermined mineral having, in this way, unfortunately been published, it seemed desirable to clear up the matter. For this purpose Dr. Earle very kindly supplied two good specimens of the mineral for investigation. Access was also given to the note-books kept by Dr. Johnston-Lavis. He had made a separate entry for each specimen and the carbon copies were placed with the specimens. The entry for ‘thermokalite’ reads in every case : ‘Thermokalite (n. sp.) by Tunnel nr. Stufe di Nerone, Baja.’ This locality is situated about nine miles west of Naples in the Phlegrean Fields (Campi Phlegraei).

The ‘Whin Sill’ of the north of England is a classic example of an igneous intrusive sheet. A detailed account of its general tectonic and petrographic features has been the subject of a recent; paper by A. Holmes and H. F. Harwood. The present author has made the attempt not so much to give a complete account of the petrology of the Whin Sill, as to describe certain peculiar developments within its mass, such as the coarse-grained bands, acid segregations, &e.

The present paper summarizes the facts at present known regarding a characteristic effect that is often produced in the fresh plagioclase felspars of igneous rocks by thermal metamorphism—namely the development of a special type of cloudiness caused by the appearance of minute inclusions. Reference is also made to certain wel|-known rocks in which the clouding of plagioclase felspars has been described without any suggestion that the peculiarity of the felspars is connected with thermal metamorphism.

About two years ago an aboriginal at Alice Springs in Central Australia reported that at a spot near the western extremity of the McDonnell Ranges the earth, if thrown upon a camp fire, did not extinguish the flames, but on the contrary increased the blaze. To those who heard the story this suggested the occurrence of oil, and it was decided to make some investigations. With the assistance of the native the spot was visited and located on the map. A sample of a white substance, which stimulated the burning of faggots, was forwarded to Adelaide University for examination and proved to be potassium nitrate. As a consequence Mr. C. T. Madigan, B.E., M.A., and myself paid a visit of inspection to the locality.

A specimen of hardystonite from Franklin Furnace, New Jersey, U.S.A., purchased in 1899 from Mr. W. M. Foote of Philadelphia for the British Museum collection consists largely of an associated pale pink mineral which has at various times been thought to be rhodonite, fowlerite, wollastonite, or scapolite. This specimen has recently again attracted attention because of the remarkable fluorescent effects it shows in ultra-violet rays. The pink mineral displays a bright brick-red fluorescence, the hardystonite a violet; and some willemite present fluoresces a brilliant green. A description in the literature of such a mineral from Franklin Furnace being unknown to Dr. L. J. Spencer, he handed over to me the problem for investigation, and a detailed examination has proved the pink mineral to be bustamite.

Introduction—Opinion is divided as to the true crystal symmetry of diamond. Some authors, notably Fersman and Goldschmidt, who have investigated its morphological and etch characters, consider it is always hemihedral, whilst others, by the same methods, have obtained results which indicate holohedrism. Early work by A. Artom showed that it was seldom piezo-electric, but more frequently pyro-electric. Van der Veen also carried out avery thorough investigation and found no piezo- or pyro-electricity in his five diamonds. These were octahedral in shape, and not very suitable for this experiment.

The material on which the following description is based was presented by Dr. A. L. Hall to the Department of Mineralogy at Cambridge, and I am greatly indebted to him and to Prof. A. Hutchinson for affording me the opportunity of describing it. The first account of the occurrence was given by Dr. Hall, recording from Aarkop, Magoloring, 'a beautiful delicately rose-coloured mica … in compact dark bluish-grey ore as thick, short, colmnnar aggregates not unlike little books of mica with pseudo-hexagonal outlines and showing the characteristic perfect basal cleavage … the mate: rial was found on the higher slopes defining the west side of Martha's Kloof'. This description was amplified somewhat in a later publication, with the addition of an analysis (see below). As noted therein the mineral also resembles that described by Chudoba as a manganophyllite allied to the phlogopite group, but the fuller description given below reveals important differences.

Accurate knowledge of the compressibility of solids was first due in a large measure to the investigations of T. W. Richards, who showed that the pressure-volume curves for sodium and potassium approximate in form to rectangular hyperbolae, that the compressibilities of the free alkali metals are nearly proportional to the atomic volumes, and that the atoms can be treated as filling the available space. Richards then endeavoured to calculate the relative volumes of the combined elements in the alkali halides, assuming that the large contraction which takes place on forming the compound was due to an internal pressure which affected equally the alkali metal and the halogen.