INORGANIC ANALYSIS 29 APPARATUS, ETC. Easy Calorimetric Methods of High Precision. W. P. White. (J. Amer. Chem. SOL, 1914, 36, 2313-2333.)-1n the calorimetric method of mixtures a, pre- cision approaching or reaching 0.1 per mille, though somewhat unusual, is often desirable, and is ordinarily not difFicult to attain with appropriate apparatus. I t s attainment is especially easy with a two-calorimeter installation, which secureB the convenienoe and high precision of differential thermo-electric temperature messure- ment.This is the only advantage of the two-calorimeter arrangement. The diminution30 ABSTRACTS OF CHEMICAL PAPERS of heat-loss error, often counted an advantage, turns out upon examination to be largely illusory. By abandoning the twin calorimeters, previously used to get this supposed advantage, and using for the comparison calorimeter a vacuum-jacketed flask, there is a gain in convenience and precision. A special thermo-electric com- bination renders the necessary temperature observations as simple as with the twin arrangement.A completely enclosing jacket of uniform temperature is necessary for this method, but this is no loss, for such a jacket proves to be necessary for the attainment of the highest precision by any method.This method is quite effective with two jackets, one around each calorimeter, and therefore with adiabatic methods. Efficient complete jackets can be very easily realised according to several methods, which are described. As compared with others, the present method is especially advantageous for observations of great absolute precision, and wherever it is desirable to secure the advanta-ges which the thermo-electric system possesses in the way of rapidity and of facility in making varied observations.The measurement of heats of dilution is cited as a type of measurement where high absolute, rather than high relative, precision is desired, since the temperature interval may be unavoidably small.G. C. J. Estimation of Sulphur in Motor Spirit. W. A. Bradbury and F. Owen. (Chm. News, 1914, 110, 163.)- The carburettor C is warmed in a water-bath, and contains 10 C.C. of the sample, which is vaporised by it stream of air through A , and burnt at the mouth of D in a water-sealed Referee trumpet tube. Extra air is fed in through B, which also supplies a small pilot flame, while the trumpet tube is being fitted, from the auxiliary carburettor. This contains sulphur-free benzene or motor-spirit, and is controlled by the cocks 2 and 3.The last traces of the sample are swept out of the carburettor, which is heated to 150" to 160" F. towards the end of the operation, by successive portions of 1 C.C. each of turpentine introduced through the side-tube and pinch-cock.Tho burner D has a gauze cap and platinum spiral, to secure complete combustion. A solution of 6 C.C. of perhydrol in 150 C.C. of water is used, at the rate of 100 C.C. per hour, to moisten the' beads in the absorption tower. The trumpet, tray, and absorption tower are finally washed, and the sulphuric acid estimated in the usual manner.With a mixture of carbon disulphide and methy- lated spirit, the Referee apparatus, using a spirit-lamp and wick, gave 71 per cent. of the theoretical sulphur, while the new apparatus gave 90, 94.2, and 95.5 per cent. Tests on benzene with the Referee apparatus differed among themselves by 54.3 pel: cent., with the new apparatus by only 6.6 per cent. 0. E. M.REPORT 31 Grain Dust Explosions.H. H. Brown. (J. I12d. and Eng. Chew$., 1914, 6, 934-937.)-Experiments are described which show that grain dusts are generally more readily inflammable than Pittsburg standard coal-dust. Dust from oats and yellow maize appears to be more readily inflammable than dust from wheat or other grain, whether the comparison be made between finely ground cereals (flour), the dust resulting from the attrition of the grain in elevators or the like, or that accumu- lating on beams, etc., in factories. Measured by means of Wheeler's apparatus (J.Chem. SOC., 1913, 103, 1715), oat elevator dust appears to inflame at 995" C., yellow maize dust at 1025"C., and wheat elevator dust at 1115' C. This method gives relative ignition temperatures, but not the lowest temperature of ignition. This latter was determined by means of an apparatus developed in the United States Bureau of Mines and described in the paper. In this apparatus the dust is ignited in air in an enclosed space, a series of experiments being conducted at varying temperatures, the pressures developed being measured. It was with this apparatus that the comparison was made with Pittsburg coal-dust, which can be saXely heated to a temperature about 100" C. higher than that necessary to initiate a violent explosion with grain-dusts. * * * a + G. C. J.