The legal formalities to be observed in assuming occupation exacted a delay of many months: accordingly, it was not until the 10th December, 1782, that a contract could be made with Mr. Graham Moyers for the erection of a meridian room and a dome for an Equatorial, in conjunction with a becoming residence for the Astronomer. Before the work was commenced at Dunsink, the Board thought it expedient to appoint the first Professor of Astronomy. They met for this purpose on the 22nd January, 1783, and chose the Reverend Henry Ussher, a Senior Fellow of Trinity College, Dublin The wisdom of the appointment was immediately shown by the assiduity with which Ussher engaged in founding the Observatory. In three years he had erected the buildings and equipped them with instruments, several of which were of his own invention. On the 19th of February, 1785, a special grant of £200 was made by the Board to Dr. Ussher as some recompense for his labours. It happened that the Observatory was not the only scientific institution which came into being in Ireland at this period: the newly-kindled ardour for the pursuit of knowledge led, at the same time, to the foundation of the Royal Irish Academy. By a fitting coincidence, the first memoir published in the Transactions of the Royal Irish Academy was by the first Andrews Professor of Astronomy. It was read on the 13th of June, 1785, and bore the title, “Account of the Observatory belonging to Trinity College,” by the Reverend H. Ussher, D.D., M.R.I.A., F.R.S. This communication shows the extensive design that had been originally intended for Dunsink, only a part of which was, however, carried out. For instance, two long corridors running north and south from the central edifice, which are figured in the paper, never developed into bricks and mortar. We are not told why the original scheme had to be contracted; but perhaps the reason may be not unconnected with a remark of Ussher’s, that the College had already advanced from its own funds a sum considerably exceeding the original bequest. A picture of the building, showing also the dome for the South Equatorial, which was erected many years later, is given on page 133.