Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

From: Braun Corporation, Catalog No. 34, Laboratory Instruments, Apparatus and Supplies, Braun Corporation (1934) pp. 228-231.
Courtesy of VWR Scientific Products Corporation



IN the selection of Electrolytic Conductivity Measuring Apparatus it is desirable that the units comprising an assembly be properly balanced and adapted for the work intended. Equipment for research work should be selected for maximum accuracy; equipment for routine testing and industrial control for simplicity and speed commensurate with a reasonably high accuracy; and equipment for educational purposes for simplicity, commensurate with a reasonable accuracy, to facilitate instruction in conductivity measurements and the electrical circuits involved in such measurements.
The Leeds & Northrup Electrolytic Conductivity Measuring Apparatus listed have been carefully and specially selected to provide suitable equipments, for research and routine laboratory investigations, industrial process control, and educational work involving the measurement of the resistance, and conversely the conductivity of electrolytic solutions. They may be employed not only for the ordinary measurement of electrolytic resistance, but also for the determination of:
Molecular conductivity Analyses of solutions of pure electrolytes
Dissociation constants Solubility of sparingly soluble salts
Degree of dissociation Basicity of acids
Titration end-points Relative strengths of acids and bases
Dielectric constants Point of solidification of fused salts
Purity of water Chemical constitution
Further information concerning these equipments, choice of equipments or cells, Electrolytic Conductivity measurement methods, or applications to specific problems will be supplied upon request.
23203 CONDUCTIVITY OUTFIT, Educational Laboratory, Leeds Northrup - This assembly is particularly suitable for physical chemistry work in the educational laboratory. It enables the student to obtain an understanding of the electrical circuits employed in different types of measurements. The potentiometer, resistance box, and tapping key form substantial parts of equipments for measurements of potential in determining hydrogen ion concentration, titrations, thermocouple temperature measurements, etc. Extra binding posts and end coils in the potentiometer afford the proper connection for electrolytic conductivity determinations. The resistance of the slide wire and the resistance box are sufficient to cover all ordinary cases. The conductivity cell is the adjustable U-Type, permitting measurements over a wide range of conductivity, and affording instructional opportunities in cell constant, transference number determinations, etc.
The assembly supplied includes the following apparatus:
Simplified Potentiometer No. 23215
Four Dial Resistance Box No. 23246
Microphone Hummer, without dry cells, No. 23254
Telephone Receiver No. 23256
Students' Conductivity Cell No. 23226
Stand and Clamp No. 23240 for Conductivity Cell
Single Contact Key No. 23250
Complete as listed ........................................................................................... Each 176.70

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