Thomas announces the new... C O R N I N G Mode l 12

Stabilized, Line Operated

4875-C10.

A new, stabilized, line-operated, expanded scale pH Meter suitable for either general purpose or critical research work in pH determinations, redox potential measurements in millivolts, or endpoint determina­tions of Karl Fischer or other polarized electrode titrations.

Can be switched instantly from normal range of pH 0 to 14 (or 0 to ±1400 millivolts) to full-scale span of any 1 pH (or 100 mv) unit and easily read to the third place. Stabi l i ty . The precision circuit components are highly stable; transistorized amplifier utilizes solid state chopper for drift-free operation. Unaffected by line variations from 105 to 135 volts.

Large Scale Meter. The 7-inch meter scale is provided with mirror and knife-edge pointer to eliminate parallax and provide excellent readability. Meter uses the superior taut-band suspen­sion of pointer rather than the conventional jewel and pivot movement.

Manual or Automatic Temperature Compensation. Manual compensator is calibrated in I e divisions from 0 to 50° C. For continuous automatic compensation, a Temperature Probe (offered as an accessory) eliminates need for manual compensation. Polarizing Adapter. Provides 5 microamperes for endpoint determinations as required in Karl Fischer procedures, etc., using platinum electrodes.

Grounding. Operates with solutions grounded or ungrounded.

Recorder Output. Ten millivolts.

pH METER Offers precision readability on full scale expansion of any 1 pH unit

Can be switched instantly from range pH 0 to 14 to full scale ex­pansion of any Ί pH unit

A l u m i n u m Housing. With chemical resistant epoxy finish; 12J^2 inches wide X 11 inches deep X 8J^ inches high. Terminal board in rear accommodates electrodes, polarizing current adapter, recorder leads and automatic temperature compensator probe. Electrodes. Size 5 inches long X J^-inch diameter, with 30-inch leads. Glass electrode is rugged and versatile, range pH 0 to 14, for use at —5° to 100° C. Calomel reference electrode is of the fiber junction type.

NORMAL SCALE pH mv

EXPANDED SCALE pH mv

Full Scale Range 0 to 14 0 to ±1400 1 pH 100 mv

Smallest Division 0.1 pH 10 mv

±0.02 pH ±2.0 mv

0.005 pH 0.5 mv

Repeatability

0.1 pH 10 mv

±0.02 pH ±2.0 mv ±0.002 pH ±0.2 mv

Relative Accuracy ±0.05 pH ± 5 0 mv At buffer +1.0mv point to 0.2% ±0.002 pH of reading Buffer and sample in same range ±0.005 pH Under other conditions ±0.01 pH

4875-C10. Corning pH Meter, Expanded Scale Model 12, as described, with one each Glass and Calomel Electrodes, Electrode Support Rod and Holder, Polarizing Adapter, 4 oz. KC1 crystals and 16 oz. Buffer Solution pH 7.00. With 3-wire cord, 3-prong plug and adapter; for 115 volts, 50 or 60 cycles a . c ; 10 watts . Without Automatic Temperature Compensator.495.00

Detailed descriptive bulletin sent upon request.

ARTHUR H. THOMAS COMPANY Scientific Apparatus and Reagents

V I N E STREET AT 3 R D · P. O. BOX 7 7 9 · P H I L A D E L P H I A 5, PA.. U . S . A .

Circle No. 102 on Readers' Service Card

1 3 0 A · ANALYTICAL CHEMISTRY

EXPANDED SCALE