There are many forms of these, and to describe them would of itself fill a volume. A simple generator for hydrogen sulphide, carbon dioxide or hydrogen is shown in Fig. 106. The acid is held in the bottle, which is provided with a tubulature. The iron sulphide, etc., is in the calcium chloride jar, B. … Read more
Gases, Drying and Absorbing.—For this purpose U-tubes, potash bulbs, calcium chloride tubes and calcium chloride jars are used. U-tubes, Fig. 103, are made in a number of forms and are suited to drying gases by the use of calcium chloride, anhydrous copper sulphate, sulphuric acid, etc. Figs, a 103 and b 103 are good forms … Read more
Laboratory Flasks may be obtained in some fifteen or twenty different forms, of which the Erlenmeyer and the globe are most used in analytical laboratories. The Erlenmeyer is shown in a, Fig. 102. It is an excellent flask in which to filter by suction (see Chapter III.), for titrations, where precipitates are to be formed … Read more
These are used in laboratories for the storage of solutions, and acids, ammonia, etc., are received in them. The problem with them is usually how to get the contents out of them. One of the easiest ways is to place the carboy in a Stevenson’s tilter. This consists of a pair of rockers so fixed … Read more
The simplest form of aspirator consists of two large bottles, a, Fig. 98, both of which are tightly stoppered with rubber stoppers. Through each of these stoppers pass two tubes, one reaching from a few inches outside to within a fraction of an inch of the bottom of the bottle, the other reaching to just … Read more
Filtration by Vacuum The vacuum or suction arrangement shown has four openings and hence four filtrations can be made at the same time. If less than this number are ample for the work to be done, the table may be shortened accordingly. In an iron and steel laboratory, where many samples of pig iron are … Read more
Measuring Apparatus.—The chief forms of these are burettes, pipettes, graduated flasks, graduated cylinders and “graduates.” Burettes have already been described, and an automatic pipette was also mentioned, both in Chapter VII. For roughly measuring reagents, graduated cylinders are usually used. These may be obtained in sizes ranging from 5 cc. to several liters. A convenient form … Read more
Assay furnaces are made to use three kinds of fuel—gaseous, liquid and solid. Those using gas are very little employed, usually only in city laboratories where but a few assays are made. They are, of course, very convenient when occasional assays are made, as in the laboratory of a consulting chemist, who is sometimes called … Read more
The apparatus used to reduce samples of ore, rock, coal, minerals, etc. from the dimensions usually encountered as they are brought to the laboratory, to the fine powder necessary for the analysis, may be divided into two classes, (1) crushers and (2) pulverizers. The former are used simply to prepare the material for the latter. … Read more
Electrolytic determinations are now part of the routine of many commercial laboratories and means for carrying out such work will usually be found in every well-equipped metallurgical laboratory, no matter how small it may be. In determining copper, nickel, bismuth, etc., the electrolytic methods are far more satisfactory than the precipitation or volumetric ones, hence … Read more