Abstract: A nesting box for birds including a front wall with an entrance aperture, a rear wall, a bottom, a roof and mounting means for mounting the nesting box on a support construction. The front wall has an opening with which one of a group of plate-like elements can selectively co-act, each of which elements has an entrance, aperture with dimensions specific to a determined category of birds, which entrance apertures of the different elements have mutually differing dimensions and can thus allow passage of birds of differing dimensions. A marking relating to the dimensions of the relevant entrance aperture is added at each entrance aperture such that the marking is visible from the outside via the opening or via a second opening.

Abstract: Solar collector apparatus comprising a panel of series connected all glass solar tubes, each tube having an outer evacuated glass cylindrical jacket with a half circular concave cylindrical reflector on its inner surface, blackened heat absorption glass tubing within the jacket secured by glass connection support means to the jacket in an offset position to lie in the focal plane of the reflector, and circulating fluid storing the energy within the heat absorption tubes.