Abstract: An aerobic system provided to treat sewage generated by a modern larger home which does not have access to a municipal sewage connection The features of this system are adaptable to upgrade and/or replace existing systems. In a preferred embodiment the system uses two 1000 gallon tanks, a first pretreatment tank to receive raw sewage, remove settleable and floatable solids from the sewage, and discharge into a second tank in which the pool of sewage is aerated. The second tank contains a motor driven aerator and a unique self-cleaning filter driven by an outgoing liquid stream from the aerator. After passing through the filter, the liquid is then discharged into a leaching field or nearby stream as permitted by the proper regulatory agency.

Abstract: A reflecting standard for an optical apparatus comprises a semitransparent crystal or glass which reflects from its front surface a predetermined proportion of the incident light dependent upon the index of refraction at the wavelength of the incident light. The rear surface of the reflector is disposed at an angle to the front surface and is provided with an antireflecting coating to minimize reflection therefrom.

Abstract: A fuel strainer assembly having an inner sleeve and an outer sleeve, the outer sleeve acting to prohibit water from passing therethrough while allowing fuel to pass, and the inner sleeve acting to permit fuel to pass therethrough but prohibit diesel fuel oil wax crystals from doing so when the fuel oil being strained is below the cloud point at which the wax crystals tend to be formed. The assembly also provides for sufficient fuel to continue to be supplied to the fuel using means even is wax crystals clog the inner strainer sleeve.