128 THE ANALYST. APPARATUS. A New Pyknometer. C. N. Riiber. (Chew. Zeit., 1903, xxvii., 94.)-The apparatus figured in the accompanying sketch is claimed to exhibit two chief advantages over other pyknometers. First, the liquid-.is brought to the temperature of observation in the separate flask A, this hastens the process much, and the pyknometer itself is not liable to become damp during a warming or cooling process ;THE ANALYST. 129 secondly, it is provided with a counterpoise C, which has exactly the weight of the pyknometer when filled with water at the standard temperature, and has also the same external volume as the pyknometer, so that, with the exception of the weights themselves (which in ordinary work may be neglected), the masses laid on each pan of the balance are identical, and corrections for displaced air, which are necessary if the results are to be exact to the fourth decimal place, are not required. The pyknometer contains 20 C.C.between the mark a on the right-hand tube and the point of the capillary b ; a cap is used to cover a if the liquid is very volatile. The flask A holds about 70 c.c., and in it the liquid is adjusted in temperature. By aspiration the pyknometer is filled a first time in order to bring the glass to the correct temperature; and then the liquid is allowed to run out, adjusted in temperature once more, made to fill B as before, and the excess withdrawn by applying a piece of filter-paper to the point b. The instrument easily gives an accuracy of O’OOO1 ; and if if is provided with an evacuated glass jacket its delicacy may reach 0.00001.I t is made by Sauer and Gockel, of Berlin, W. F. H. L. A Modification of Thorne’s Receiver for Distillations in Vacuo. Zd. H. Skraup. (uonatshe,t’te f. Chem., xxiii., 1162.)- The advantage claimed for this piece of apparatus is its simplicity. The end A of the receiver shown in the figure is connected to the distillation flask, the side-tube B to the pump. The tap D has one very wide bore; E is a three-way tap by means of which air may be admitted to the bottle. This is connected by B rubber stopper, which remains on the tube when the bottle is changed, which opera- tion is greatly facilitated by moistening the inside of the neck of the new bottle with a drop of the distillate. The rest of the manipula- tion is evident froffi the figure.I r;iD A. G. L.130 THE ANALYST. C. Schmitz’s Portable Apparatus for Gas An&lysis. (Chem. zed. 1902, xxvi., 1202.)-This apparatus has been specially designed for safe transport, and for con- venience in use by not requiring any dis- mounting of its parts. The filtering vessel e communicates at its right-hand end with the inlet rubber tube d, and at the left, past the three-way cocks at the top of each absorp- tion vessel and the burette, with the aspirat- ing ball g. By this arrangement practically all the gas left in the apparatus from a pre- vious test can be swept out before a fresh charge is admitted. The burette a is joined to its jacket, which contains water, by fusion. The absorption vessels, each filled with glass tubes, are also jacketed, and the reagents, admitted through the rubber tubes at the base of each, enter into the annuli. The necessary reagents are stored in bottles fitted with wired-clipped stoppers, which stand in separate compartments of the case. A t the point h in the case is a movable clip which carries both the inlet tube and the tube lead- ing to the aspirator; when this is drawn forwards the tubes extend horizontally and sideways from the case, and are held so that they cannot become kinked ; when the case is to be closed the clip is pushed back. The bottle .i goes into the space 0. F. H. L.