Abstract: A hand-held calculating device for calculating Federal Income Taxes or the like includes substantially flat, elongate front and rear cover members and an insert card. Suitable structure is provided for joining the cover members with the card slidably insertable therebetween. The card bears a plurality of columns on both front and rear sides thereof, each column bearing a plurality of lines of tax figures or the like. A number of through apertures or windows are provided on both front and rear cover members for viewing selected lines and columns of figures on the insert card.

Abstract: A container is made by attaching an inner member to a rotational mold, extending across the interior of the mold and terminating near the interior surface, and forming a container in the mold by rotational molding.

Abstract: Polymers of ethylene having a melt index of at least 10 are simultaneously rotationally molded and crosslinked by an acetylenic diperoxy compound to produce molded articles having high impact strength and stress cracking resistance.

Abstract: A hollow multilayered article is rotationally molded by introducing into the mold particles of a hompolymer or copolymer of ethylene containing a crosslinking agent and heating the mold during rotation thereof to melt this first polymeric layer. Solid particles of a different polymer are then introduced into the mold at a time after at least substantially all of the particles of the first polymer have melted and prior to the time when the inner surface of the first layer would become smooth and glossy. The mold is then rotated and heated to melt the second polymer. The mold is then cooled and the multilayered article removed.