30 A
ANALYTICAL
CHEMISTRY
3
ONLY Ο BATTERIES complete with batteries and electrodes
PHOTOVOLT pH Meter Mod. 125
$145.-
Powered by 3 ordinary radio batteries which give 2000 hours reliable service. Simple and fast in operation. ACCURATE DEPENDABLE RUGGED PORTABLE Write for descriptive Bulletin #7 78 to:
PHOTOVOLT CORP. 95 MADISON AVENUE · NEW YORK 16, Ν. Υ.
THE
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IMPROVED
MELTING POINT APPARATUS ( D E N N I S TYPE) A rapid method for testing materials melt ing between room temperature and 250° C.
Samples are tested on a silver coated bar of solid copper, one inch square by 17 inches long. Art electric heater and thermoregulator at one end pro duce a thermal gradient along the bar so that a wide temperature range is always available. A thin train of sample laid on the surface will melt at a definite point. Temperature at this point is determined by contact with a sliding constantan pointer to form a copper-constantan thermocouple. The new Series 3821 apparatus is equipped with an improved pointer and slide for smooth operation with good visibility and positive, uniform pressure. Ask your dealer for prices, or write for Spec. 3821.
PARR EST. 1899
INSTRUMENT CO., MOLINE, ILLINOIS MAKERS OF CALORIMETERS AND PRESSURE REACTION EQUIPMENT
