In the year 1807 work was commenced on this building by the General Government, the site having been ceded by the city. It was intended to erect a strong fortification, to be called Castle Clinton, but, in 1820, it was discovered that the foundations were not strong enough to bear heavy ordnance, and Congress reconveyed the site to the city. The building was then completed as an opera house, and used for operatic and theatrical performances, concerts, and public receptions. It was the largest and most elegant hall of its kind in the country, and was a favorite resort of pleasure seekers. Jenny Lind sang there, during her visit to the United States. It was used for this purpose until the year 1855, when, the fashion and wealth of the city having removed too high up town to make it profitable, it was leased to the Commissioners of Emigration, as a landing-place for emigrants. This Commission has the exclusive charge of the Landing Depot and its inmates. It is composed of six Commissioners, appointed by the Governor of the State. The Mayors of New York and Brooklyn, and the Presidents of the Irish and German Emigrant Societies, are members _ex-officio_. They are responsible to the Legislature for their acts. The Landing Depot is fitted up with quarters for the emigrants and their baggage, and with various stores at which they can procure articles of necessity at moderate prices. As most of them come provided with some money, there is an exchange office in the enclosure, at which they can procure American currency for their foreign money. Many of them come furnished with railroad tickets to their destinations in the West, which they have purchased in Europe, but the majority buy their tickets in this city. There is an office for this purpose in the building, at which the agents of the various lines leading from the city to the Great West are prepared to sell tickets. No one is compelled to transact his business in the building, but all are advised to do so, as they will then be fairly treated; while they are in danger of falling into the hands of swindlers outside. Attached to the establishment is an official, whose duty it is to furnish any information desired by the emigrants, and to advise them as to the boarding houses of the city which are worthy of their patronage. The keepers of these houses are held to a strict account of their treatment of their guests. The majority of the emigrants go West in a few days after their arrival. Some have already decided on their place of future abode before leaving Europe, and others are influenced by the information they receive after reaching this country. Should they desire to remain in this city they are frequently able to obtain employment, through the Labor Exchange connected with the Landing Depot, and by the same means many obtain work in other parts of the country--the Commissioners taking care that the contracts thus made are lawful and fair to both parties.