Abstract: An air bearing straight line tracking phonograph tonearm combines the features of a readily removable decoupled counterweight arm which bears horizontally and vertically adjustable counterweights; a readily removable tonearm tube with tapered wall thickness having an integral headshell, cartridge and stylus; various simple means for vertical and leveling adjustments; and a vertical tracking angle or stylus rake angle control that automatically retains perfect tracking tangency.

Abstract: An improved drop-ceiling support system for supporting ceiling tiles and lighting fixtures comprises hanger members attached to and extending downwardly from an original ceiling and arranged at aligned intervals along parallel rows, inverted U-shaped carrier channel members adjoined end-to-end in parallel rows and attached to the hanger members, and main runner members adjoined end-to-end in parallel rows transverse to the rows of carrier channel members and snap-fitted beneath and into the carrier channel members.

Abstract: A structure for illuminating vertical displays such as pictures or the like includes a rectangular window in the ceiling whose front and rear edges are spaced from the display area so that lines extending between such front and rear edges, and the top and bottom edges of the display area, are approximately between 15.degree. and 45.degree. to the vertical. A series of spaced inclined slats registering with the window have specular front faces and light absorbing rear faces and are inclined, related and dimensioned to direct and confine the ambient exterior light traversing the window to the display area. In one form the slats lie in forwardly downwardly converging planes and have top edges terminating in rearwardly directed flanges lying in a horizontal or inclined plane and a light modulating grid plate may be provided having alternate laterally extending opaque and transparent stripes overly the flanges and the plate is transversely adjustable.