350 THE ANALYST, APPARATUS. Improved Beckmann Apparatus for Molecular Weight Determinations. J. McC. Sanders. (Proc. Chew. Xoc., 1906, xxii., 165.)-The difficulty of equalizing the overcooling for parallel observations with the solvent and solution, and in the \ c n q U A 11 U i addition of ice crystals for inducing congelation, in the ordinary Beckniann apparatus is overcome by the use of a modified form of inner tube. A narrow, almost capillary tube (A) is fused into the bottom of the solution tube, and attached to a thin rubber tube and small rubber bulb (B). The con- tained tube is placed in an outer jacket the’wall of which is in contact with the side tube A. The liquid in A is first completely expelled by compressing B, and the rubber tube pinched while B is removed, allowed to fill itself with air, and replaced, when on releasing the rubber tube a small amount of solvent rises in A, which, in operation, being nearer to the source of cold, freezes first, and at the moment desired a mass of crystals can be projected into the main body of the solvent by a sharp compression of the bulb B.C is a pneumatic stirrer, an adaptation of the photographic ‘‘ shutter release,” the piston and cylinder being of aluminium or glass, ground to fit perfectly, and the agitator E being made by flattening and twisting a piece of platinum wire, which is, then coiled into a spiral form, and the other end of the wire attached to the piston. The spring is of hard-drawn aluminium or platino-iridium wire, A small vertica tube (D) passing through a third hole in the rubber stopper replaces the ordinary side tube of the Beckmann apparatus, and serves for the introduction of the substance.The apparatus can be adapted from a small Soxhlet extraction tube by cutting off theTHE ANALYST. 351 upper and lower parts and the wide side tube, and bending the narrow siphon into the form of A. W. H. S. A Simple Form of Rotating Electrode for Eleetro-chemical Analysis. (Chem. News, 1906, vol. 93, p. 283.)-In the apparatus shown F. Mollwo Perkin. in the figure, the vessel in which the elec- trolysis is carried out consists of a tap-funnel, which allows of easy washing of the cathode without interrupting the current. The elec- trodes are made of platinum alloyed with 20 per cent. of iridium, which forms a very rigid alloy.They are of wire 1 mm. in diameter; the anode consists of a few wide turns, whilst the cathode has a, large number of turns, and a total surface of 23 square cms. The electrodes may preferably be sand- blasted. A nickel wire may also be used as cathode and will last for a large number of determina- tions, being but little attacked by the nitric acid used in removing the deposited zinc, copper, etc. I n six copper analyses made with this apparatus the error ranged from 0 to 1.3 mgms., on from 0.05 to 0.13 gram of copper. The author mentions that Johnson, Matthey and Co. now supply iridium of 99 per cent. purity ; the metal is as hard a8 steel, unattacked by boiling aqua regia and by molten lead. It cannot be drawn into wire, but may be rolled into sheets whilst hot.A. G. L. A New Burner for Spectroscopic Work. E. H. Riesenfeld and H. E. Wohlers. Fig. 1, consists in electrolysing the solution to be examined in the interior of a, Tech burner, the fine spray produced by the gas bubbles at the electrodes being carried up into the flame by the current of air sucked in by the gas. The burner is made in two parts, an upper one B fitting on a support C ; the support also carries the vessel A, which holds 2 c.c, of the liquid to be tested, and into which dip the platinum-iridium wire electrodes. The current should have a strength of 0-2 to 1 ampisre at 8 to 16 volts. For metals such as copper or thallium, which are easily deposited, a current reverser should be inserted in the circuit, and the current reversed every minute, Fig.2 shows a convenient arrangement of the whole, B being the current reverser; the lamp used as resistance (Chem. Ztg., 1906, xxx., 704.)-The principle of the burner, shown in FIG. 1.352 THE ANALYST. is conveniently utilized to illu- minate the scale of the spectro- scope. The 2 C.C. of liquid used suffice to give an intense and steady spectrum for two hours, at the end of which time the vessel will re- quire filling up with water. The spectrum disappears as soon as the current is interrupted, the current of gas cleaning the burner at once. The burner may also be used as a convenient source of monochro- matic light. The apparatus may be obtained from Franz Hugers- hoff, of Leipsic. FIG. 2. A. G. L. @ a + @ @ @ THE SALE OF FOOD AND DRUGS ACTS: SOME DEFECTS AND SUGGESTED REMEDIES. AN intelligent and moderately written article. on the above Acts has recently appeared in the pages of our contemporary, the PharrnaceuticaZ Journal of August 25, 1906, from the pen of Richard A. Robinson, junior, barrister-at-law, and assistant editor of that paper. Most of the points contended for have long been recognised by all thoughtful public analysts; indeed, so far is this the case, it is owing to this recognition that the joint committee of this Society and the Pharmaceutical was appointed to cope with cases of difficulty in drug adulterations. At the same time it should be remembered that the public analyst is not always to blame for ill-advised prosecutions ; he is not the prosecutor, but is bound to analyse and report upon any sample sent him by his Authority, and, though he may give his opinion that a prose- cution in a certain case would be unadvisable, this opinion may or may not be acted upon by the body under which he serves. . s , * @ 4 3 + W. J. S.