A dock light for mounting in a void in the side of a floating dock. The supply shaft connecting members connect a supply shaft to the frame, and the take-up shaft connecting members connect a take-up shaft to the frame. The receiving means can be configured to receive spectral emission from the samples in a variety of ways, e. A photoresponsive transistor can conveniently be utilised for this purpose. In some embodiments, identification of the secondary source, such as a ratings service comprising information which may supplement the subject of a search query, is based upon information entered by the user. Each output signal contribution of each output signal has an output-side contribution offset in relation to the corresponding amplified input signal, which depends on the amplified input signal that supplied the output signal contribution, and the output signal to which the output signal contribution contributes.