A two chamber electrically pumped electron beam stabilized gas discharge laser is enabled to operate at lower electron accelerating voltages for given power applications through provision of very thin separating diaphragms. The apparatus is controlled throughout initial pump down, laser gas filling, laser operation and air release phases to prevent occurrence of a diaphragm rupturing pressure differential between the two chambers or the inadvertent malsequencing of chamber evacuation and backfil...

A device for spectroscopic measurement of a gas composition wherein a helium resonance lamp includes a window partially transparent to radiation at 584A which is emitted by said lamp, the window being within a chamber. The gas to be sampled is mixed with He and placed in the chamber and the lamp is excited. Spectral radiation from the chamber is viewed and analyzed through an observation window.

Polarizing interferential systems having a light source, a compensator element, an object, and a beam splitter element in optical alignment which utilize only a single birefringent wedge in the compensator element and only a single birefringent wedge in the beam splitter element are useful for the study of objects exhibiting light amplitude and/or phase properties. By tilting either the optic axis with respect to the light system, the entire wedge or both, it is possible to eliminate the dual we...

The invention contemplates a telephoto-lens construction comprising four parts, one or more of which is a multiple-element part, and so devised as to achieve superior achromatic quality over a wide field of view, within a structural length which is less than the focal length. This result is achieved by following a particular schedule of regions from which to select optical glasses for the respective parts, or for the respective multiple elements of one or more of such parts, and by forming lens ...

A flow chamber which is particularly useful in slit-scan photometry and which has a predetermined configuration for orienting generally flat oval particles such as squamous cells in the direction of fluid flow such that the maximum cross-sectional area of each particle is substantially normal to a light path traversing the flow of particles at an observing station situated along the flow path of the particles.

In a method for operating an attenuated total reflection infrared system for measuring the concentration of a constituent in a liquid process stream wherein a sample of the stream is irradiated with a beam of radiation at a wavelength, corresponding to the characteristic absorption wavelength of the constituent, the improvement comprises intentionally irradiating the sample with a beam of radiation at a wavelength longer than the characteristic absorption wavelength of the constituent.

A comprehensive top camping set which includes a convertible flashlight to lantern combination, a cooking utensil for holding cans of food and preventing the same from spilling, an electrically operated simulated camp fire, a toy hatchet which is convertible into an imprinting member for making markings such as an animal's paw in the ground, a toy knife having a whistle in the handle thereof for producing an animal sound or the like, a toy gun which has a light transmitting scope device for proj...

A microscope illumination system having a zoom unit located before the field diaphragm is useful to provide maximum illumination for objectives from 10 to 110X, when using a suitable condenser, without the disadvantages of other systems. The zoom unit comprises a positive lens, a negative lens and a positive lens in series with the two positive lenses connected together and movable with respect to the negative lens along the optical axis as a unit.

In the analysis of liquids, a whole liquid sample is absorbed onto an absorbent and porous sample carrier, such as a filter paper, and is then traversed by an eluting fluid to carry away one or more constituents of interest for analysis. Elution is preferably carried out under pressure. A sample holder comprises a simple plug and socketed body which are adapted to receive in clamping engagement therebetween a rigid plate of porous material, which acts as a support for a sample carrier.

A zoom lens providing variable magnification in a short fixed object plane to image plane distance in which a lens barrel contains a prime lens and a low power, air-spaced doublet coaxial with and at one end of the prime lens, the doublet combining with the prime lens to provide a plurality of magnifications at the image plane of objects at the object plane upon synchronized movement of the lens barrel and one element of the doublet with respect to the lens barrel and the other elements to a plu...