Abstract: A double-beam, time-sharing, ratio-recording spectrophotometer in which the reference signal data is evaluated both in an actual demodulation cycle and in a different cycle, which may be either a preceding or a following cycle. The two evaluations are combined to produce derived reference signal data. Ratioing means are included for extracting the ratio between the sample signal data evaluated in an actual demodulation cycle and the derived reference signal data. Predetermined multiplying factors may be used in arriving at the derived reference signal data. The interpolation of reference signal data from actual and non-actual demodulation cycles enables the effect of uncompensation on photometric accuracy to be minimized. Uncompensation results from the fact that in a time-sharing spectrophotometer sample and reference signal data do not occur at the same time and do not therefore relate to the same environment and the same wavelength.

Abstract: In a device such as a spectrophotometer with an associated chart recorder in which the speed ratio between a first displaceable member and a second displaceable member may be selectively changed within a predetermined range of speed ratios, in a first embodiment of invention which is mechanical in nature, a number of gear trains in constant mesh with each other are provided to obtain the different speed ratios. Each of the gear trains has associated therewith a rotary disc with circumferentially even spaced apertures, the gear train obtaining an input from the first displaceable member by means of arms rotatable concentric with the discs, the arms carrying a pin adapted to enter into positive engagement with any one aperture, the number apertures depending on the scale served by the associated gear train.

Abstract: Automatic sample preparation method and apparatus for making successive measurements with an analyzer by picking up with a single stepwise movable metering probe, in a first measuring cycle, a sample for measurement from a sample container and a small volume of air; introducing this sample and the air into the inlet of the analyzer; picking up with the same metering probe, in a secondary measuring cycle, a sample for measurement from the same sample container and a small volume of air, and picking up with said metering probe a metered quantity of liquid additive and a second small volume of air; and thence introducing said sample, said liquid additive and said air picked up in the secondary measuring cycle into the inlet of the analyzer.

Abstract: A unity magnification catoptric image-forming system and an illumination system on the one hand, and an object- and image-surface supporting means on the other hand, are arranged for relative movement to retain the object and image surfaces in unity magnification conjugate planes of the catoptric system while effecting a scanning-type exposure of successive portions of the image surface to successively illuminated portions of the object. Fine motion mechanisms permit accurate preliminary adjustment of the object- and image-receiving surfaces relative to each other while under visual examination with the aid of the catoptric image-forming system.

Abstract: Where the unknown leg of a bridge is a sensor which presents a resistance that relates to a parameter by a second order polynomial, a negative feedback circuit from the conventional null measurement terminals to a voltage divided point in the balance leg thereof is included to provide a substantially linear relationship between the parameter of the sensor and a ratio including two voltage levels from the feedback circuit. A circuit means for continuously monitoring this ratio of voltages with a counter in recurring cycles for digital display is incorporated with the linearized bridge circuit of this invention in a particular embodiment thereof.

Abstract: A completely automated kinetic analyzer particularly suited for performing classical kinetic chemistries on an ultra-micro scale. The analyzer comprises a sample preparation unit and a photometric analytical unit. The preparation unit includes a rotationally indexed tray of sample containers presented in timed sequence to a diluter probe which effects dilution of the samples while transferring them sequentially to respective reaction cups, batches of which are contained in magazines and previously filled, by means of an automatic pipetter, with a first reagent. Conveyors move the magazines in stages through the preparation unit, the sample-reagent mixtures meanwhile undergoing preincubation. A second automatic pipetter thereafter adds a second reagent to each cup, in turn the contents of which are then mixed by an automatic stirrer.

Abstract: An automatic sample preparation device for use in flameless atomic absorption spectroscopy or the like, wherein samples to be examined for a particular element are successively mixed with graduated, metered additions of the element to be determined, which includes, in combination, controlled delivery pumping apparatus, a storage vessel system containing dilution agents connected to the inlet side of the pumping apparatus, a dosing probe connected to the outlet side of the pumping apparatus, a stepwise movable carrier, a plurality of sample containers mounted on the carrier, a sample withdrawing device for withdrawing samples from the carrier, and a control unit for moving the dosing probe with respect to the carrier so that one group of at least two successive sample containers on the carrier can be simultaneously mixed with graduated, metered additions of the element to be determined prior to sample withdrawal.

Abstract: In a measuring instrument such as a spectrophotometer which is driven under the control of a dedicated microcomputer and has a provision for wavelength scan, a flow chart lock system is obtained by storing in the random access memory of the microcomputer an indication of the actual chart position between two sprockets on the chart drive. With this information and stored data regarding the position of the scanning apparatus of the instrument, accurate repositioning of the chart to accurately reflect the scanning position even after scale changes or different modes of operation have occurred is accomplished.

Abstract: The invention is directed to method and apparatus for introducing liquid samples into a gas chromatographic column by supplying a liquid sample to a heated injector in a continuous, uniform and relatively slow-moving flow; vaporizing the sample in the heated injector; passing the vapor through a supply line in the injector to a restrictor, vented to the atmosphere, until stationary conditions have been established; and then passing the vapor to the gas chromatographic column for sampling by reversing the flow in the supply line for a relatively short time.