quote:

The old Round Tower at the mouth of Portsmouth Harbour was begun by Edward III and finished by Henry VIII. At its base may be seen the chains which reached across the harbour, at this point only a quarter of a mile broad. In the days of torpedo-boats, Spithead was no longer a safe anchorage, and in times of war, the great ships would probably be collected in the harbour, so that some kind of boom would be needed across the entrance to afford protection, as was usual in the old days. In the photograph the flagship Majestic is seen entering the mouth of the harbour.