Appleton’s Dictionary of Greater New York And Its Neighborhood (1905):
Blackwell’s Island (Roosevelt Island)
…is in the East River beginning opposite E. 50th St and extending northward. It is a long, narrow strip of land containing about 120 acres and is the property of the city of New York. It is also one of the group of islands upon which are the public charitable and correctional institutions for which New York is famous. Upon it are the penitentiary, the almshouse, lunatic asylum for females, workhouse, blind asylum, city hospital, hospital for incurables and convalescent hospital. The majority of these buildings are of granite, of imposing size and are unique in their way. They have been built from stone quarried on the island and by convict labor. There is a rudeness about the work which is quite in accord with the style of architecture, which is a turreted and battlemented design of the feudal character. Around the shores of the island, too, are heavy granite seawalls, all built by the convicts at a comparatively small cost to the city. The island is fertile and farming and gardening are carried on, all by convict labor… In the summer time and especially from the New York shore channel, the island is as attractive as it is imposing in appearance. In the penitentiary building are confined person convicted of misdemeanors and the average number of inmates is about 1,200. The population of the entire island is estimated at about 7,000 persons all told.
Atlas of the city of New York (1885)
View looking south from the top of one of the island piers (1905)