Ivan Simon

Spectroscopy in Infrared by Reflection and Its Use for Highly Absorbing Substances

The infrared spectra of many strongly-absorbing solids and liquids can be measured directly only with difficulties, involving preparation of very thin sections, or mulling the substance with diluents, etc. In such cases, the measurement of reflection offers an advantage. If the measurements are performed at two different angles of incidence, the two optical constants, namely, the refractive index n and the index of absorption κ of the studied substance can be obtained. A graphical method for obtaining n and κ from the measured reflecting powers is described and due corrections for the apparatus polarization are given. An alternative method for obtaining the optical constants from a single set of measurements at normal incidence is indicated for a case of a simple resonance band. This method is based on the impedance concept of the reflecting medium. Experimental arrangement for reflection measurements, using a standard infrared spectrometer, is described. Examples of measured reflecting powers and optical constants derived from them are given for the cases of quartz, mica, and liquid carbon tetrachloride.

Sensitive Tiltmeter Utilizing a Diamagnetic Suspension

A tiltmeter of the horizontal pendulum type is described whose mass consists of a diamagnetic material suspended in a potential well of a suitably shaped magnetic field. The depth of the potential minimum determines the restoring force acting upon the mass and consequently the pendulous frequency and sensitivity of the instrument. In this manner the elastic forces usually supplied by fine springs or fibers are replaced by field forces and the mass is free to respond to tilts or accelerations without any trace of friction of external (Coulomb) or internal (anelastic) origin. The required amount of damping is obtained from eddy currents induced in the seismic mass by its motion in the field. The instrument requires no power to operate the suspension and it can be used over a wide range of temperatures. Under usual environmental conditions, it requires no temperature control. Some of the preliminary results obtained with the tiltmeter in measurement of earth tides are discussed.

New Method for Measuring Linear Compressibility of Solids

An apparatus is described for measuring linear compressibility of rods and tubes under hydrostatic pressures to 4000 kg/cm2 and temperatures to 260°C. The measurements are made by means of a linear‐differential transformer located on the outside of the nonmagnetic high‐pressure container. The differential transformer makes it possible to determine the position of a small iron cylinder affixed to the sample. Compressibility of vitreous silica determined by this method was obtained as −ΔV/V=p(26.43–0.0049t) ×10−7+p2(21.8–0.040t)×10−12; compressibility is expressed in relative volume change, p in kg/cm2 and t in °C.

Technique for Measurement of Specific Volume of Liquids at High Pressures and Temperatures

A novel method is described for measuring specific volume of liquids at high temperatures and pressures. The displacement of the two ends of a continuous column of the liquid is measured. One end is maintained at high temperature and pressure while the other is at normal conditions.