THE ANALYST. 371 APPARATUS. A New Areo-pyknometer. P. N. Raikow. (Chem. Zeit., 1902, xxvi., 704-)- The apparatus shown in the accompanying diagram possesses several advantages over the areo-pyknometers already devised by Eichhorn and by Van- denvyver, inasmuch as the temperature of the liquid under investigation need not be the same when it is inserted in the bulb as when its density has to be determined. Also it is possible to determine the specific gravity of the liquid on the same portion thereof at different temperatures in succession. The pyknometer is constructed in two parts -a lower, o t, and an upper, p Z. o is the usual weight of mercury or shot, a is an empty space, and b is the liquid reservoir. The upper part con- sists of a pair of concentric tubes, d and c , the smaller of which is 1 milli- metre in diameter, joined together at their ends, and containing in the annulus the ordinary pyknometer scale.At their base the united tubes become the stopper p , through which d passes, terminating in a cone to prevent entanglement of air. The stopper is given nearly parallel sides, is about 15 millimetres long, and is very carefully ground in. At the top the inner tube d expands into the funnel I, which holds about 0.5 C.C. The reservoir b is filled with the liquid to the mark s, which is in such a position that when the upper part is inserted in the neck the said liquid reaches slightly above the point n. The temperature of the whole is then adjusted, and the surplus liquid (that above n) is removed with a small pipette or a piece of poroua paper.After immersing the apparatus in distilled water and taking the reading, the temperature of the liquid may be raised by placing it in warmer water, removing, as before, the surplus fluid; while if the second reading is to be made at a lower temperature than the first, a drop or two of liquid is added to the funnel to make good the con- I d c-- u - 0372 THE ANALYST. traction. apparatus may be made suitable for investigating any desired quantity of liquid. By altering the size of the reservoir, or by omitting it altogether, the F. H. L. The Cause of the Destruction of Platinum Crucibles in Phosphate Analysis, W. C. Heraeus. (Zeits. f. angew. Chem., 1902, xxxvii., 917.)-The destructive agent is phosphorus, which may be liberated under certain circumstances by the reduction of the magnesium phosphate.The author found by experiment that carbon causes the reduction at 950" C., and reducing gases-especially hydrogen-act at a con- siderably lower temperature. An even more dangerous reducing agent is ammonia. It is very important that this substance be driven off at a moderated temperature before raising the crucible to red heat. Ammonia acts far more energetically on the magnesium phosphate if the latter contain free ammonium phosphate, which is liable to be carried down by the precipitate when ammonia and phosphoric acid are present in excess. This condition of things may often occur at the moment of precipitation, but if the precipitate be allowed to stand some time before filtering, the ammonium phosphate will go into solution again.If the precipitate be dried before being ignited, the drying should be carried out at 100" C., for at 130" or 150" a change takes place whereby phosphoric acid is set free. A. M. REVIEW. CANE-SUGAR AND THE PROCESS OF ITS MANUFACTURE IN JAVA. GEERLIGS, Director of the West Java Sugar Experiment Station. Edition. (Office of Cane-Sugar. Altrincham. Price 5s.) By H. C. PRINSEN Second This is a small, well-written book of about 100 pages, by a most competent author, and, although one would expect from its title and size that its contents would be very limited in their scope, it will be found to supply valuable information useful to chemists engaged in cane-sugar factories in localities other than Java. Besides giving a, clear and concise account of the mode of manufacture, there is a large amount of information respecting the composition of the sugar-cane and the various products derived therefrom, and in addition other data of practical impor- tance to the factory chemist. The contents of the book are divided into four parts : I. The Raw Material. 11. Sugar Manufacture. 111, Chemicals used in Cane-Sugar Manufacture. IV. Tables. B. E. R. N.