Abstract: An apparatus is disclosed for determining the position of a moveable element in a three-dimensional workspace near a mounting surface. A sound source is provided in the moveable element. A plurality of at least three housing units are adapted to be secured to said mounting surface in spaced relationship to one another. A sound sensor is mounted on each of the units, and a sound source is mounted on at least some of the units. The positions of the sound sensor and the sound source of said at least some of the units can be adjusted. Means are provided which are responsive to the sound from the sound source of at least one of the units and received at the sound sensor of another of the units, for computing the distance between the sound source of said one of the units and the sound sensor of said another of said units.

Abstract: Construction for roof of greenhouse consisting of triangular glazed panels are hinged together and removable to provide a sawtooth construction when assembled and placed over a rectangular base.

Abstract: Disclosed is process for extracting fungi-toxic material from wood material of a species of wood which is resistant to fungi-growth. The process comprises providing a first quantity of the wood material, contacting said quantity with an extraction agent in an amount and for a time sufficient to extract essentially all fungi-toxic material in the wood material, separating the agent containing the fungi-toxic material from the wood material, contacting a second quantity of wood material with the separated extraction agent for a time sufficient to extract fungi-toxic material contained in the second quantity of wood material, and separating the extraction agent from the second quantity of wood material.

Abstract: A resilient support for seats comprising telescoping members with a plurality of resilient members positioned therein in a series relationship with the telescoping members' relative movement; a plurality of resilient members stacked in a series relationship between the telescoping members, the resilient members each having an equal or different shore durometer hardness; an adjustment member for preloading said resilient members; and a lubricious bushing positioned between the contacting surfaces of the telescoping members.