Russians testing submarines at Port Arthur acccording to the Dutch newspaper Soerabaijasch handelsblad dated 28 April 1904

An item dated The Hague, Netherlands 27 April referred to telegrams from Port Arthur reporting that the Russian experiments with submarines were very successful.(1) This was the first time that the presence of submarines was mentioned. Until now was only known that a few weeks ago admiral Makaroff asked for sending some boats by train.