A portable enclosure, easily erectable and collapsible, to provide environment control and prevent contaminants from being released from the enclosure. The method includes receiving data to be transmitted to a receiver, determining information on the structure of the received data, segmenting the received data into segments, in a manner determined responsive to the determined structure information and transmitting the segments to the receiver. One of the housing members being provided with an opening to allow a portion of one of the other housing members to extend through, and where the extending housing member contains within its interior a number of internal fluid passages for fluidly connecting the hydraulic pump to the hydraulic motor. The lighting system is at least partially submerged in the aqueous liquid. At the time of measurement of a sample, an amplification factor of the photomultiplier is controlled by a negative high-voltage controller according to measurement requirements, or measurement is performed after an optimum detector signal voltage is set by controlling the amplification factor of the detector signal output from an amplifier.