The general characteristics of the jet-apparatus for dreging were studied in the previous report. The theoretical equations derived were found to agree with the experimental data.
　In this second report a special type of the jet-apparatus which is used as a pressure increaser in the suction pipe of a dredging pump was tested for the transport of water only and the mixture of water and sand. The experimental results showed good agreement with the theoretical ones except for the case of a large area ratio of jet nozzle to suction pipe. From this experiment the jet-apparatus which ejects the water jet toward the suction mouth from the outside was confirmed to increase the sand transport capacity of a dredging pump by mixing sand around the jet nozzle by forwarding mined sand into the suction pipe, and by increasing the pressure in the suction pipe.