THE ANALYST. 297 APPARATUS, ETC. New Apparatus for the Estimation of Carbon. A. Kleine. (Clz,enz. Zeit., 1909, 33, 376.)-The wet combustion apparatus shown in the first figure is characterised by the fact that the condenser carries both air- entry and gas-exit tubes. The air-inlet tube is provided with an opening through which air can enter the flask even when the bend of the tube is stopped up by chromic acid. The basket carrying the sample is suspended from EL projection on the same tube in such a way that it remains suspended by its longer wire after it has been inverted by inclining the flask. The soda-lime phosphoric anhydride tube shown in the second figure is provided with a glass disc in one of its limbs, as shown. Through this glass disc go three short tubes, on which is placed an asbestos plug, and above this phosphoric pentoxide, the remainder of the tube being filled with soda-lime.The tube can still be used even after the asbestos has become moist with phosphoric acid, as the glass disc prevents contact with the soda-lime. A. G. L. FIG. 1. W FIG. 2. The Emerson Fuel Calorimeter. C. J. Emerson. (The Chem. Eyi?zeer, 1909, 9, 113-114.)-The calorimeter is of the bomb type, and differs from existing intruments in being made in two cup-shaped pieces, held together by a large nut at298 THE ANALYST, the centre. The lower part carries the capsule, and is shaped so as to fit into a special holder without screwing, The calorimeter vessel is tapered to fit the lower part of the bomb, less water being required, aad a greater rise in temperature being obtained thereby.The pipe con- veying oxygen to the bomb is made of a short rigid piece of metal instead of the usual flexible tubing. It is stated that these modifications make the bomb more suitable for use by an inexperienced operator without impairing its accuracy. The lining is of porcelain or metal, as before. A. G. L. The Munroe Crucible. W. 0. Snelling. (J. Amer. Chem. Soc., 1909, 31, 456- 461.)-It is pointed out that C. E. Munroe was the first to describe a crucible of the Gooch type containing platinum sponge as the filtering medium (Chem. News, 1888, 58, 101). Such crucibles are prepared by precipitating a concentrated solution of chloroplatinic acid with a slight excess of ammonium chloride, washing the preci- pitate first with water and then with alcohol, and pouring it, to a height of 0-25 to 0.5 cm., into a platinum crucible with perforated bottom held firmly on a pad of several layers of filter-paper.As soon as the excess of alcohol has been absorbed by the filter-paper, the crucible is dried in a water-oven; cap and cover are then put on, and the crucible is cautiously heated to dull redness. 8hould the sponge so obtained show any cracks, it may be pressed together, or patched by adding fresh chloroplatinic acid and igniting. A firmer mat is obtained if a disc of fine platinum gauze is first placed in the bottom of the crucible ; a second similar disc may also be placed on top if the crucible is used for precipitates requiring mechanical removal. By gently rubbing the mat with a hard object a smooth polished surface is obtained, which sometimes is an advantage, but makes filtration slower.Platinum filters are generally much quicker than asbestos filters. A. G. L. Determination of the Specific Gravity of Small Quantities of Liquids. H. von Wartenberg. (Ber. deut. Chem. Ges., 1909, 42, 1126-1131.)-1t is some- times desirable to ascertain the specific gravity of a liquid of which only very small quantities are available. The author has applied to this purpose the ‘( micro- balance” of Nernst. After numerous attempts, he has succeeded in obtaining reasonably accurate results by the use of small capillary pipettes weighing, when empty, from 0.009 to 0.035 gram, and containing from 0.4 to 2 C.C. of liquid. The pipettes are of the usual shape, and are filled by inserting the bulb, by means of the forceps, in a rubber collar fixed in the end of a tube provided with a stopcock, and sucking the liquid up into the bulb. When the bulb is full, the stem of the pipette fills itself by capillary attraction. The pipette is then suspended on the micro- balance in a horizontal position by means of a wire support, and the deflection of the balance is observed. The determination is made more accurate by calibrating the balance with liquids of known specific gravities, within certain convenient limits, so that the pipette when filled with the lightest liquid stands at zero on the balance- scale, and shows the maximum deviation when it is filled with the heaviest liquid of the series.The smaller the range of the series selected, the greater is the accuracy of the determination, and the values of the scale readings, with the zero andTHE ANALYST.299 maximum points fixed by any given liquids, are plotted in the form of curves for reference. The error8 of working are caused, on the one hand, by volatilisation during weighing, since no caps can be carried on the pipette, and, on the other hand, by the presence of traces of liquid on the outside of the point of the pipette, The former error is only sensible in the case of liquids which are more volatile than water ; the latter error may be reduced in the case of aqueous liquids by drawing the point of the pipette between two slightlygreasy fingers. After a series of determina- tions, the zero point should again be checked by means of the lightest standard liquid of the scale, in order to see that the adjustment of the balance has not altered, With volatile liquids, such as ether and chloroform, the average error amounts to about +O-005 in the specific gravity.With aqueous liquids, a pipette of the maximum dimensions mentioned above, and a smaller range between the zero and the maximum points (1.0 to 1*5), the error can be reduced to about k0.00025. No special means are available for ascertaining the temperature of the liquid in the pipette, so that it is necessary to fill and weigh this at a constant temperature. J. F. B. A Compressed-Air Wash-Bottle. E. Dowzard. (Amer. J. Plzarm., 1909, 81, 174-176.)-This apparatus will be found useful where compressed air is available.A flask of 2 or 3 litres capacity is provided with a two-holed rubber stopper, as shown in the figure. A limb of the T-piece A passes through one perforation of this stopper ; this T-piece should have a horizontal tube twice the diameter of the vertical tube. The tube B nearly touches the bottom of the flask, its other end passing through the horizontal limb of the T-piece C, and being held in position by the stopper D The vertical limb of C is con- nected with A by the rubber tubing E. To the end of the tube B in the T-piece C any desired length of narrow rubber- tubing is attached (say about 2 feet), and a glass jet, F, is joined on the end. A piece E of rubber-tubing about twice the diameter of the narrow tube is passed over the latter and joined to the T-piece C at G. The other end is attached to the glass- tube H, which has a perforation, 6 mm. in diameter, at the side. The glass jet is fixed in this tube as shown by means of the stopper I. By means of hooked copper wire, this tube can be attached to the neck of the flask. The end of the T-piece A is connected with the compressed-air main by rubber tubing. When the air is300 THE ANALYST. turned on it passes out at H, but if H be closed by the finger, it passes into the flask and forces water out through the jet F, the force being regulated by allowing some air to escape at H if necessary. A. R. T.