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ANALYTICAL
CHEMISTRY
tor accurate, uiL*~^ RELY ON A ICOLEMAN ELECTROMETER -τ-
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MODEL 3D.
For dependable accuracy a pH meter should have these features: 1. Both pH and millivolt scales. 2. Automatic Temperature Compensator for pH. 3. Redox electrode for oxidation-reduction potentials. You'll find all three in Model 3D Coleman electrometers. The scale-changing switch allows instant reading of pH over the range of 0-13 pH or 0-1300 millivolts. The scale is easily readable to two-hundredths pH or one millivolt. Electrical accuracy is 0.1% on either scale. By using battery power, voltage fluctuations as experienced with line-operated meters are avoided. Electrochemical accuracy is within 0.05 pH. Model 3D is also adaptable to other technical applications, such as the determination of end points in titrations. For a reliable, portable, versatile instrument, choose a Coleman Model 3D, available from stock. No. 11694 Coleman Electrometer 3D, complete with sealed glass, reference, and Redox electrodes, buffer solution and batteries, each $235.00
APPARATUSCO.,INC. SCIENTIFIC GLASS LABORATORY APPARATUS - INSTRUMENTS
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- CHEMICALS -
GLASSWARE
THE IRVING LITER for Bunsen Burners •
no more matches •
operated with one hand •
ready for instant use •
fits
all Bunsen Burners
• reduces fire hazard Lighting a burner with a safety match requires two hands. The IRVING LITER leaves one hand free to hold a test tube or other equipment. Matches, after being used, are messy if thrown on the floor and clog the drain if thrown in the sink. The IRVING LITER is attached firmly and permanently to the tube of any Bunsen Burner from % inch to % inch o. d. There is no temptation to carry improvised torches from one burner to another — a real fire hazard.
TRY ONE DOZEN IN YOUR LABORATORY AND YOU WILL NEVER GO BACK TO MATCHES (No risk — they may be returned in 30 days for full credit.)
No. 4768. IRVING LITER-Per Doz
W. M. W e l c h S c i e n t i f i c
$5.00
Company
1515 Sedgwick St., Dept. A. Est. 1880 Chicago 10, Illinois, U.S.A.
