Abstract: An apparatus for controllably varying the sample volume for each of a plurality of sample lines used with air monitoring equipment is disclosed. The sample volume is varied depending on the compound or compounds of interest sampled through each line. The flow volume from each sample line is determined and controlled by proportional time that an electrically actuated valve is open for that sampling line.

Abstract: An apparatus for controllably varying the sample volume for each of a plurality of sample lines used with air monitoring equipment is disclosed. The sample volume is varied depending on the compound or compounds of interest sampled through each line. The flow volume from each sample line is determined and controlled by proportional time that an electrically actuated valve is open for that sampling line.

Abstract: A wire return spring for providing bias for brake shoes in a drum brake system urging the brake shoes to deactuated positions, with the wire spring having a circular like contour as assembled with the brake shoes.

Abstract: A single-coil wound on a ferrite core surrounding a current path is driven from a voltage controlled constant current source. The coil drive current is modulated with a fixed frequency squarewave. The average voltage present across the coil is sensed and integrated to provide an output signal which is proportional to the current flow and also provides a negative feedback to the voltage controlled current source to bias the modulated drive current in a direction which compensates for the biasing effects of the current flowing in the conductive path.

Abstract: A card game containing a plurality of transparent playing cards. Each playing card has a like number of similarly located playing sections with one or more indicia located within the playing section. Guide means, such as a plurality of guide cards or a table covering, are used to align each participant's playing cards. Some guide cards have one or more markings located thereon which, in the play of the game, serve the same function as the indicia on the playing cards. During the play of the game, each participant attempts to play his playing cards directly down upon each other in overlying relationship in such a manner that the indicia on two or more playing cards are not superimposed.