Abstract: Disclosed is a portable electronic probe device, including a memory system, which is useful for measuring the pH and temperature of a liquid. The pH sensor consists of a glass electrode-reference electrode combination. The temperature sensor is made up of a thermistor fitted into a well enclosure at the bottom of the probe. A display box attached to the probe contains a memory system. The pH and temperature value is received by the memory system as an electrical signal. The signals are amplified, converted from analog to digital data, and stored in a digital memory.The pH and temperature data, and the precise location at which the measurement is taken, appear continuously as digital displays in a transparent panel on the display box. When the memory is full the probe device is placed in a charger stand to re-charge a battery in the memory system by a magnetic "coupling" sequence.

Abstract: A method and portable apparatus for measuring particulate concentration in the atmosphere utilizing uniform laser pulses to traverse the atmosphere to be measured and a photo-electronic receiver which discriminates against stray light and detects the attenuation of the laser pulses. This attenuation is caused by particulates in the atmosphere which tend to scatter or absorb light. By using monochromatic laser pulses having wavelengths lying in transparent atmospheric windows, error is not introduced by the attenuation of the beam due to gases occurring naturally in the atmosphere including water vapor. Thus concentration of particulates such as smoke, fog, smog, dust and the like are measurable.