A body of liquid contained in a ring-shaped piece of tubing serves as a liquid pendulum. Changes in the elevation angle of the support on which the tubing is mounted cause the tubing to rotate relative to the liquid; this relative rotation is sensed by means of a pair of capacitor electrodes coupled to the liquid, variations in capacitance causing energization of a driving motor in a direction to rotate the tubing back to a null position. The amount of rotation of the support, and hence the elevation angle, is indicated on a digital voltmeter supplied from a potentiometer mechanically coupled to the shaft which rotates the tubing.

A level apparatus for indicating the orientation relative to vertical of a surface of an object extending along a user line of sight, including a fluid vessel containing an indicator fluid including a liquid and having a fluid surface, the fluid vessel having a vessel abutment region with a rearward abutment wall for placing against a surface of an object to be evaluated for tilt and with a forward display wall including a fluid display window extending generally perpendicular to the user line of sight, the fluid surface being visible in the fluid display window when the abutment wall is substantially upright, and includes a vessel reservoir region extending at least one of: rearwardly and forwardly from the vessel abutment region along the user line of sight, the vessel abutment region and the vessel reservoir region being in mutual fluid communication.

A device for continuously monitoring the orientation of an individual's physical posture relative to a path the individual is traversing includes a transparent tube attachable to the bill of the individual's cap, and extending beneath and to opposed sides of the bill, a pair of fastening elements with each fastening element securable to an end of the tube so that the tube can be secured to the bill by the fastening elements, and a spherical member disposed and visible within the bore of the tube and susceptible to shifting therein as a result of the individual's movement while traversing the path.

A personal water rescue device. A gas device is connected to a housing and releases gas bubbles. A light device is contained within the housing and illuminates the gas bubbles. The light device includes a pair of vials that contain chemicals that when mixed form chemical illuminance and which communicate with inwardly deformable bulging ribs on the housing so as to allow mixing the chemicals and forming the chemical illuminance when the inwardly deformable bulging ribs are squeezed and their displacement ruptures the pair of vials. A tubular member of the housing terminates in a pin that punctures the gas device when the tubular member is further threaded into a connector sleeve of the housing, and in so doing, releases the gas bubbles for heads up surface positioning for a disoriented water victim, while the chemical illuminance from the light device provides illumination therefor.

A novel apparatus and method for use in measuring surface slope is disclosed. In a preferred embodiment, the measurement apparatus includes a fluid case having an arch of flat segments forming a sloped ceiling. In another preferred embodiment, a smooth curve, instead of a series of flat segments, is formed by reducing the length, and increasing the number, of the constant slope flat segments. And in a preferred embodiment, the apparatus provides a mechanism for compensating for any expansion or contraction of the fluid in the fluid case. A method for measuring the slope of a surface includes providing a measurement apparatus, placing the measurement apparatus adjacent the surface and reading an indicator corresponding to the slope of the surface.