Abstract: An improved cigaret filter wherein dry and active green algae in the form of chlorella in a granular or powdery form which can physically trap and remove such toxic substances contained in cigaret smoke as nicotine, tar, carbon monoxide and the like and, additionally, can biologically denature and change these substances to harmless form are carried or held by a carrier comprising a fibrous, continuous-cellular foamed or the like member. The filter is used as combined with a cigaret holder or directly with a cigaret. With each carrier, preferably, a total weight of 20 to 50 mg. of granular or powdery chlorella is used alone or as combined with such inorganic porous adsorbent as fine granular or powdery zeolite, silica gel, iron oxide or activated charcoal.

Abstract: A cigarette holder with a filtering means capable of chemically denaturing such harmful substances as nicotine, tar and the like and particularly carbon-monoxide gas contained in cigarette smoke to harmless substances, in addition to mechanical trapping of them. The filtering means contains hydrogen peroxide solution preferably of a concentration in a range of 0.5 to 3% and an amount in a range of 0.1 to 0.3 c.c. for achieving the chemical denaturalization.

Abstract: A wide-angle door viewer providing a large wide-angle outdoor view which can be zoomed and is readily perceptible without closely approaching the eyepiece, which comprises an optical lens barrel having relatively large diameter lenses in positions of reverse Galileo system, a mounting barrel for mounting the lens barrel to a door or the like, and a zoom barrel fitted slidably to the mounting barrel and having a relatively larger diameter eyepiece on which the large view is provided for direct but distanced observation.

Abstract: An optical spyglass of a compact dimension to be mounted in a house door or the like for providing to an interior viewer a substantially 180.degree. wide-angle outdoor view. Its optical system comprises a wide-angle lens having a convex surface of a large radius curvature and an opposing convex surface of a small radius curvature for converging incoming light of substantially 180.degree. outdoor sight at a large rate, an objective having a concave surface and butted coaxially on the side of the concave surface of the lens for collimating the converged light to be of a small confined diameter, an eyepiece having a convex surface disposed coaxially with the objective and spaced therefrom for magnifying the collimated light to be of a normal view of the outdoor sight. Such optical system is secured in a substantially tubular barrel body disposed closely around the collimated light of the confined diameter.

Abstract: An improved cigaret filter wherein dry and active green algae in the form of chlorella in a granular or powdery form which can physically trap and remove such toxic substances contained in cigaret smoke as nicotine, tar, carbon monoxide and the like and, additionally, can biologically denature and change these substances to harmless form are carried or held by a carrier comprising a fibrous, continuous-cellular formed or the like member. The filter is used as combined with a cigaret holder or directly with a cigaret. With each carrier, preferably, a total weight of 20 to 50 mg. of granular or powdery chlorella is used alone or as combined with such inorganic porous adsorbent as fine granular or powdery zeolite, silica gel, iron oxide or activated charcoal.