摘要:

THE ANALYST. 205 APPARATUS, ETC. Apparatus for Rapidly Measuring and Delivering Liquids. F. Schubert. (0esterr.-ungar Zeit. ZzickerimL u. Landw., 1907; through Chenz. Zeit. Rep., 1908, 32, 53.) -The apparatus may be in the form of a burette or pipette. The plug of the tap is hemispherical, as shown in the illustration. When the tap is turned, as shown in Fig. 2, the pipette is in communication through the side- tube with a large vessel containing the solution in bulk. The tap is then turned, as in Fig. 1, to deliver the portion of liquid measured off in the pipette. If the tap is turned, as in Fig. 3, the solution may be drawn directly from the containing vessel. w. P. s. A New Autoclave. B. Pfyl and B. Linne. (Chem. Zeit., 1908,32, 205.)-The aiithors describe a new pattern of digester, suitable for conducting hydrolyses and other operations in presence of carbon dioxide under pressure.The apparatus (see figure) consists of a stout cylinder of phosphor bronze, C, about 31 cm. long, with an internal diameter of 2 to 3 cm., and an external diameter of 4 cm. The upper end carries a, screw thread by which the head, A, can be attached, a tight joint being made by a lead washer. The bead, A, contains a ball check-valve, which allows gas to enter the cylinder, but prevents its exit ; a manometer is also screwed into the side of the head. At the top there is a cap, H, which may be screwed over the head. The substance under treatment is contained in a glass tube, G, which fits into the cylinder. After the insertion of the tube the head is screwed on, and connected by means of its top screw with a gas cylinder containing carbon dioxide, nitrogen, or oxygen.Gas is admitted until the manometer registers a higher pressure than is required €or the work. The gas reser- voir is then removed, and, since the ball-valve is not quite tight, gas is allowed to escape until the pressure on the mano- meter is just right; the cap, H, is then screwed on. The digester is heated in a glycerol bath or air-bath, and is con- structed to work at pressures up to fifty atmospheres. After the experiment is finished the cap, H, is removed, and the gas allowed to escape slowly past the ball-valve. J. F. B. New Dephlegmator for the Fractionation of Petroleum. V. F. Herr. (Chenz. Zeit., 1908, 32, 148-149.)-The new fractionating column consists of the outer mantle of a Liebig condenser, 30 to 100 cm.in length, placed-vertically. The206 THE ANALYST. lower side-arm of the mantle is sealed off, the upper one serves for the exit-tube, a thermometer is inserted in the top, and a basket of wire gauze is placed at the bottom, whilst the whole space inside is filled with lead shot, of which about six should weigh 1 gram. If temperatures of only 130" C. or less are required, the column is merely insulated by meam of cotton-wool, filter-paper, and asbestos. For higher temperatures, the column is surrounded by an annular copper oven, kept at, e . ~ . , 300' C. by means of four burners; a smrtll air-spkce should be left between the column and the inner tube of the oven. To give good results, the dephlegmator should not be allowed to contain much liquid.A. G. L. Simple Manometer for Vacuum Distillation. N. L. Gebhard. (PYOC. C h m . SOC., 1908, 24, 51.)-The manometer described consists essentially of a barometer tube bent in the form depicted in the figure. The simple trap ,-I provents effectually any air from being forced back into the barometer tube and thus affecting the readings. I n order to remove any air thus trapped, it is merely necessary to incline the apparatus so that the mercury expels the air into the open arm again. This is, however, only necessary at the end of an operation, as the apparatus is capable of yielding accurate readings in spite of the presence of air in the trap. .sharply at zero interposed. Pellin's New Polarimeter.Sidersky. ( AIZIZ. de c l ~ i i i ~ . anal., 1908, 13, 14-15.)-1n this polarimeter the field of vision shows concentric zones, which renders the reading easier and more sensitive than in the old type of half-shadow instruments. I n order to obtain the effect of two concentric zones in the latter, a circular disc is cut from the quartz plate in front of the prisms, and cemented to the centre of a transparent disc, or the latter may be cemented to the pierced quartz plate. By cutting an annular disc from the quartz and fixing it to a transparent disc, or this disc to the quartz, three concentric zones are seen in the field of vision, forming a dark ring on a clear ground, or t h e versa. The pronounced contrast thus produced disappears or at the point observed when an optically active substance is C.A. M. Laboratory Pump. R. Luther. (Chem. Z e k , 1908, 32, 267-268.)-The pump is designed chiefly to circulate water at constant temperature, and may be driven directly by an ordinary electric motor of high speed. I t consists essentially of a number of metal tubes rotating in a metal drum, which suck up water from an opening at the bottom of the drum and eject it through a tube at the side. Coupled to a small motor, the pump is capable of dealing with 9-5 litres of water per minute, raising 5 litres to a height of 160 cm. or 9 litres to a height of 15 cm. I t is made by F. Kijhler, of Leipsic. A. G. L.THE ANALYST 207 Device for Washing Precipitates. E. Blumner. (Chem. Zeit., 1908, 32, 232.)-The apparatus is designed for rapid washing of precipitates by upward filtration, and consists of a perforated porcelain disc placed below an inverted funnel connected with a filtering flask.The filter-paper is fastened to the disc by a rubber band supplied with the apparatus, which is made by H. Gockel, of Berlin. A. G. L. A Simple Form of Release for Victor Meyer’s Vapour Density Apparatus. T. S. Patterson. (Clzcm. Nezus, 1908, 97, 73.)-Into the upper part of the neck of an ordinary Neyer’s apparatus, a cork, H, having an eccentrically placed hole, F, t inch in diameter, is fitted, while the rubber stopper, D, carries in a slanting position a glass tube of inch bore. When all air has been expelled from the apparatus in the usual way, the stopper, A, is removed, and the Hofmann tube, G, containing a weighed quantity of the substance to be examined, is introduced as shown in the figure, The G- stopper, A, is replaced, and when desired, the little tube may be dropped into the bulb of the apparatus by moving the tube, B C, with the hand until the Hofm,ann tube is brought over the hole in the cork, H. The tube is thus always kept in a vertical position, and no leakage can occur until the hot region of the bulb is reached. ‘ A. R. T.

ISSN:0003-2654    

DOI:10.1039/AN9083300205

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

THE ANALYST 207 REVIEW. MEDICAL LABORATORY METHODS AND TESTS. By HERBERT FRENCH, M.A., M.D. Second (Oxon.), F.R.C.P. (Lond.), Assistant Physician, Guy’s Hospital, etc. edition. Price 5s. net. Published by Baillihre, Tindall and Cox. This work, as stated in the preface, is ‘‘ intended to be a small handbook for the medical laboratory.” It deals with the examination of urine, blood, sputum, pus, gastric contents, and faxes ; microscopical examination in affections of the skin ; the examination of serous exudations, cerebro-spinal and cystic fluids ; the preservation and staining of morbid anatomy specimens ; and tests for the common poisons. When all this is attempted to be dealt with in 175 small octavo pages of fairly large type, it is evident that the author has set himself a by no means easy task.With the more purely medical part of the work it is not in our province to deal, though as far as a layman can judge it appears to give a good deal of general information which may be useful to the medical student or to the general practitioner who has not had time to specialise in laboratory work. The toxicological section, however, which more nearly208 THE ANALYST. concerns the Public Analyst, occupies less than five pages. When it is noted that within this compass the author attempts to give directions for the detection of bella- donna, opium, strychnine, arsenic, carbolic acid, chloral, coal gas, copper salts, corrosive sublimate, hydrochloric acid, lead salts, nitric acid, oxalic acid, phosphorus, prussic acid, and sulphuric acid, serious criticism seems scarcely called for.Otto’s method of separating alkaloids from vomit is described in nine lines, and the chemical reader will receive a rude shock on being told to look for morphine in an ethereal extract, and another when told to test for arsenic by holding a cold saucer in the flame of the original obsolete form of Marsh’s apparatus. Any medical man attempting a toxicological investigation with no better guidance than he here gets would court the fate deserved by an amateur attempting to deal with matters beyond his knowledge, and one naturally thinks of the old adage, Ne sutor, etc. There have been, however, and still, happily, are, among us medical men who have made the study of the chemical aspects of toxicology a large part of their life-work, and it is to the well-known standard treatises of such authors, whose names are too well known to need inention, that the student .who wishes to become an expert in such delicate work must turn for guidance, rather than to such scrappy and hastily compiled instructions as are offbred to him in this little book. B. D.

ISSN:0003-2654    

DOI:10.1039/AN9083300207

出版商:RSC    

年代:1908

数据来源: RSC