Accordingly, a form of organization was adopted which contemplated the formation of a large association of members, and a continual increase of the endowment funds and the collections of the Institute. Provision was made for a subdivision of the membership into departments, representing various branches of art and science, each department forming a society by itself and yet enjoying all the privileges of the general association. A general invitation was extended to citizens specially interested in science and art to become members of the Institute. Courses of lectures on science and art were provided. The directors' room of the Institute was enlarged to accommodate the meetings of some of the departments contemplated, and a large lecture-room on the third floor of the Institute building was fitted up at an expense of $2600 for the occupancy of those departments that would make use of apparatus and collections at their meetings. During the first fifteen months after the reorganization of the Institute a membership of three hundred and fifty persons was recorded. The Brooklyn Microscopical Society joined the Institute in a body, with sixty-four members, and became the Department of Microscopy. The American Astronomical Society, whose members resided mostly in New York and Brooklyn, became the Department of Astronomy, with thirty-two members. The Brooklyn Entomological Society united with the Institute, and became the Entomological Department, with forty-one members. The Linden Camera Club of Brooklyn became the Department of Photography, with twenty-six members. Departments of physics, chemistry, botany, mineralogy, geology, zoölogy, and archæology were successively formed. Each of the above twelve departments began to hold monthly meetings. The permanent funds and property of the Institute were increased $3000. Additions were made to the library, and its circulation increased from 12,000 to 36,000 volumes per year. The lecture courses were fully attended. The classes in drawing were enlarged, and a general citizens' movement to secure a museum of arts and sciences for Brooklyn was inaugurated.