GENTLEMEN,--I scarcely need refer in a letter to you to the modest beginning and gradual growth of the institution over which you preside, and of which you are the responsible guardians. But we have arrived at a period in its history when its inauguration gives to it and to you some degree of prominence, and which must stamp our past efforts with weakness and inconsideration, or exalt those of the future to the measure of liberality necessary to certain success. You have a building erected and instruments engaged of unrivaled excellence; and it now remains to carry out the suggestion of the Astronomer Royal of England in giving permanency to the establishment. The very distinguished Professors BACHE, PIERCE, and GOULD, state in a letter, which I have been permitted to see, that to expand this institution to the wants of American science and the honors of a national character, will require an investment which will yield annually not less than $10,000; and these gentlemen say, in the letter referred to,-- "If the greatness of your giving can rise to this occasion, as it has to all our previous suggestions, with such unflinching magnanimity, we promise you our earnest and hearty coöperation, and stake our reputation that the scientific success shall fill up the measure of your hopes and anticipations." For the attainment of an object so rich in scientific reward and national glory, guaranteed by men with reputations as exalted and enduring as the skies upon which they are written, contributions should be general, and not confined to an individual or a place. For myself, I offer, as my part of the required endowment, the sum of $50,000 in addition to the advances which I have already made; and, trusting that the name which you have given to the Observatory may not be regarded as an undeserved compliment, and that it will not diminish the public regard by giving to the institution a seemingly individual character, I remain, Gentlemen, your obedient servant, BLANDINA DUDLEY. Judge HARRIS then introduced the Orator of the occasion, Hon. EDWARD EVERETT, whose speech is given verbatim in these pages. THE INSTRUMENTS OF THE DUDLEY OBSERVATORY. During the Sessions of the American Association, the new Astronomical Instruments of Dudley Observatory were described in detail by Dr. B. A. GOULD, who is the Astronomer in charge. We condense his statements:--