Regarding neutral losses figures are even less definite. Only Norway, which again is by far the heaviest loser amongst neutral nations, has published official statements covering her losses. For six months, July to December, 1917, her losses were 127 boats of 216,000 tons. For the entire year 1917, they amounted to 434 boats of 686,800 tons and involved the death of 401 sailors, while 258 more were missing or unaccounted for. Holland, amongst other losses, reported the sinking by a mine off the Dutch coast on August 3, 1917, of the steamer _Moordam_ of 12,531 tons. Mines in one case, and an explosion in the other, were responsible for the sinking of two British steamers: _City of Athens_, of Cape Town, of 5,600 tons, on August 10, 1917, with the loss of nineteen lives, of which five were Americans; and _Port Kembla_, of 4,700 tons, on September 18, 1917, off Cape Farewell. Regarding the German losses in U-boats, practically no definite information is available. Only occasionally has any news managed to get by the censors of the Allies, and the Germans, of course, are entirely silent on the subject. On November 24, 1917, one U-boat was sunk by the United States destroyers, _Fanning_ and _Nicholson_, while on patrol service in European waters. Her crew were captured with the exception of a few members who were drowned. Two other U-boats were reported to have been sunk during December in the Ionian Sea by a French destroyer. This, of course, does not represent the total losses inflicted by the Allies on the German U-boat forces. Indeed, it has been stated officially that the average loss amounts to thirty-eight U-boats per month. Naval engagements between units of the various belligerents were comparatively few and unimportant. As a result the losses incurred by the different navies, at least as far as they became known, were likewise comparatively slight. During August, 1917, British monitors cooperated with the Italian navy in bombarding successfully Austrian positions in the Gulf of Trieste. On August 16, 1917, there was also a slight engagement between British and German destroyers in the North Sea without result. On September 1, 1917, British destroyers destroyed four German armed mine-sweeping vessels off the coast of Jutland. Three days later, September 4, 1917, a German submarine bombarded Scarborough, killing three persons, wounding five, and doing some material damage. During the successful German attack against Riga in the early part of September, 1917, German submarines appeared in the Gulf of Riga and bombarded the city.