The Harlem River, flowing into the East River, divides Manhattan from Ward's Island, and this, with Randall's Island to the north and Blackwell's Island to the south, forms the group of "East River Islands" upon which are the penal and charitable institutions of the great city. The chief of these are on Blackwell's Island, a long, narrow strip stretching nearly two miles in the centre of East River, and barely more than two hundred yards wide. It covers one hundred and twenty acres, and has the penitentiary, almshouses, workhouses and hospitals, the spacious buildings being of granite quarried there by the convicts. Over on the New York City shore is the extensive Bellevue Hospital. In cases of vagrancy and minor crimes, the offender is said to be "sent up to the Island." Ward's Island has a surface of two hundred acres, and here are the Lunatic Asylum and Emigrant Hospital. Randall's Island has the institutions for children and idiots, while upon Hart's Island, out in Long Island Sound, are industrial schools and the pauper cemetery. The buildings are all upon a most elaborate scale, and it costs over $2,000,000 for their annual maintenance. A steamboat ride along East River, with these extensive establishments and their well-kept grounds passing in review, is a most interesting suburban excursion. The Long Island shore to the southward of Ward's Island is thrust out in a way that curves and contracts the East River passage, which, turning eastward just below where the Harlem River comes in, goes through the famous Hell Gate to reach the Sound. Formerly, the swift tidal currents boiled and eddied through this dangerous pass, Hallett's Point, jutting out from Long Island, narrowing the channel, and Pot Rock, Flood Rock, the Gridiron and other reefs making navigation perilous. Many were the wrecks here, and frequent ineffective efforts were made to improve the passage. The Government finally undertook the work in 1866 under a comprehensive plan projected by General Newton. His first task was the removal of the Hallett's Point reef, a mass of rock projecting three hundred feet into the stream and throwing the whole tidal current coming in from the Sound against the great opposing rock called the Gridiron. He first sunk a shaft upon the Point and excavated the inland side so that it made a perpendicular wall which was curved around, and designed for the future edge of the river. From the shaft, tunnels were bored into the reef under the river in radiating directions, being connected by concentric galleries. The design was to remove as much rock as possible without letting the water in from overhead, and then to blow the rocky roof and supporting columns into fragments and remove them at leisure. This work began in 1869, the shaft being sunk thirty-two feet below mean low water and the tunnels drilled out, inclining downward under the river. In 1876 the task was finished, and thousands of separate dynamite blasts had been placed in the roof and