Bulletin de l'Académie Royale de Belgique, Nos. 9 and 10. Classe des Sciences.—On some new Caligidei of the coast of Africa and the Azores Archipelago, by P. j. van Beneden.—On an optical atmospheric phenomenon observed in the Alps, by F. Folie (see Notes).—On a state of matter characterised by the mutual independence of the pressure and the specific volume, by P. de Heen. It is easily shown that the density of saturated vapour at the critical temperature is variable, and depends, at constant pressure, upon the proportion of liquid enclosed in the tube. Experiments were made in order to decide whether this independence of pressure and volume was shown also at other temperatures. The liquid chosen was ether, and the volume of liquid and vapour contained in a sealed tube was read by means of a cathetometer. A series of results showed that during condensation by pressure the density of unsaturated vapour was greater than that of saturated vapour, or that the specific volume increased with the pressure. This is an experimental verification of Prof. James Thomson's pseudo gaseous state of matter.—On the most complete reduction of invariant functions, by Jacques Deruyts.—Ex-meridian observations made at the Royal Observatory of Belgium from March to October, 1892, by L. Niesten and E. Stuyvaert.—On a new fluorine-derivative of carbon, by Frédéric Swarts. This is a liquid, of the formula CCl5F, boiling at 24°˙7, insoluble in water, and unaffected by sulphuric and nitric acids. Its density is 1˙4944; an alcoholic solution of potash destroys it gradually, forming potassium chloride, fluoride, and carbonate. It was obtained by treating carbon tetrachloride with a mixture of antimony trifluoride and bromine in equal molecular proportions. It is notable that the bromofluoride produced by the mixture acts not as a bromising but a fluorising agent.—On a simplification of some of Tesla's experiments, by H. Schoentjes. Like some recent workers in England, Prof. Schoentjes has found that most of the experiments can be produced, although with lesser intensity, without the bobbin immersed in oil, the discharge exciter, and the condenser, simply by the first Rhumkorff coil, whose dimensions need not exceed 7 X 17 cm.—On a process of sterilisation of albumin so1utions at 100°C., by Émile Marchal. Albumin can be easily sterilised at 100°C., without coagulation, by first adding 0˙05 gr. per litre of borax, or 0˙005 of ferrous sulphate in a 2 to 5 per cent. solution, or 4 to 5 gr. nitrate of urea per litre of 10 per cent. solution. The “incoagulable albumin” thus obtained is perfectly suitable for cultivations.