FREAS

Freas Electric Laboratory Apparatus

DEPENDABLE -- DURABLE -- ECONOMICAL

Freas Tube Furnace

A dependable scientific apparatus for making explosive tests of pulverized materials of every description.

The material to be tested is enclosed in a glass tube, which is then inserted in a metal tube and securely sealed before placing in furnace. The heavy composition hood is a protection against injury, in case contents of tube should cause explosion.

This furnace is constructed of the most durable materials and its operation is entirely automatic.

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For Sale by all Laboratory Apparatus Dealers

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A Portable, Precise Potentiometer

is part of the Elliott-Acree Apparatus. It is a self-contained instrument, operating on the Northrup Pyrovolter principle, and renders the complete outfit strictly portable. Readings are given directly by deflections. One scale embodies p values from -1.5 to +15, and another values from 2 to 9, with a precision of 0.003 рH. The accuracy is guaranteed to be within 0.2 per cent. of full scale throughout the life of the instrument.

Ask Us About The New Elliott-Acree Apparatus
PYROLECTRIC INSTRUMENT COMPANY

Electrical Precision Instruments

636-640 East State St.

Trenton, New Jersey

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WELCH

Specialty

TH

Demonstration Balance

HIS new form of Demonstration Balance enables the most accurate verification of the principles of moments. The adjustments permit of varying the conditions in the greatest number of ways. The center of gravity may be changed so as to be either below, on the level with, or above the knife edge. The knife edge itself is a very delicate construction and is made by allowing two very hard steel points to rest in two V shaped grooves. The counterweight on the pointer permits of adjusting its weight. The plumb bobs on the scale pans and support permit of accurately leveling this apparatus and make it possible to make the forces act in the exact perpendicular to the length of the lever arm. The scale and a clamp which holds the knife edge are both adjustable and the entire is mounted on a tripod base with leveling screws. Nickel plated throughout, making a very handsome appearance.

W. M. WELCH SCIENTIFIC COMPANY Manufacturers, Importers and Exporters of Scientific Apparatus 1516 Orleans Street

CHICAGO, ILL., U. S. A.