The library, once established, grew apace. From time to time, huge folios and quartos were added to it by purchase or donation, from which nobody profited more than Franklin himself with his insatiable avidity for knowledge. The first purchase of books for it was made by Peter Collinson of London, who threw in with the purchase as presents from himself Newton's _Principia_ and the _Gardener's Dictionary_, and continued for thirty years to act as the purchasing agent of the institution, accompanying each additional purchase with additional presents from himself. Evidence is not wanting that the first arrival of books was awaited with eager expectancy. Among Franklin's memoranda with regard to the Junto we find the following: "When the books of the library come, every member shall undertake some author, that he may not be without observations to communicate." When the books finally came, they were placed in the assembly room of the Junto; a librarian was selected, and the library was thrown open once a week for the distribution of books. The second year Franklin himself acted as librarian, and for printing a catalogue of the first books shortly after their arrival, and for other printing services, he was exempted from the payment of his annual ten shillings for two years. Among the numerous donations of money, books and curiosities made to the library, were gifts of books and electrical apparatus by Thomas Penn, and the gift of an electrical tube, with directions for its use, by Peter Collinson, which proved of incalculable value to science in the hands of Franklin who promptly turned it to experimental purposes. When Peter Kalm, the Swedish naturalist, was in Philadelphia in 1748, "many little libraries," organized on the same plan as the original library, had sprung from it. Non-subscribers were then allowed to take books out of it, subject to pledges of indemnity sufficient to cover their value, and to the payment for the use of a folio of eight pence a week, for the use of a quarto of six pence, and for the use of any other book of four pence. Kalm, as a distinguished stranger, was allowed the use of any book in the collection free of charge. In 1764, the shares of the library company were worth nearly twenty pounds, and its collections were then believed to have a value of seventeen hundred pounds. In 1785, the number of volumes was 5487; in 1807, 14,457; in 1861, 70,000; and in 1912, 237,677. After overflowing more contracted quarters, the contents of the library have finally found a home in a handsome building at the northwest corner of Locust and Juniper Streets and in the Ridgway Branch Building at the corner of Broad and Christian Streets. But, never, it is safe to say, will this library, enlarged and efficiently administered as it is, perform such an invaluable service as it did in its earlier years. "This," Franklin declares in the _Autobiography_, "was the mother of all the North American subscription libraries, now so numerous.