“The Trustees of Columbia College shall cause to be struck, with suitable devices, a medal of gold, nine-tenths fine, of the bullion value of not less two hundred dollars, to be styled “THE BARNARD MEDAL FOR MERITORIOUS SERVICE TO SCIENCE,” and shall publicly announce that a copy of the same will be awarded, at the close of every quinquennial period, dating from the probate of this my last Will and Testament, to such person, whether a citizen of the United States of or any other country, as shall, within the five years next preceding, have made such discovery in physical or astronomical science, or such novel application of science to purposes beneficial to the human race, as, in the judgment of the National Academy of Sciences of the United States, shall be esteemed most worthy of such an honor. And I make it my request that the said National Academy of Sciences shall charge itself with the duty of declaring to the Trustees of Columbia College, aforesaid, at the close of every term of five years, as above defined, the name of the person whom they judge worthy to receive such medal, with a statement of the reasons on which their judgment is founded; and that upon such declaration and nomination, the Trustees shall proceed to award the said medal, and shall transmit the same to the person entitled to receive it, accompanied by a diploma or certificate attesting the fact and the occasion of the award. But, if the National Academy of Sciences shall judge that, during the five years preceding the date at which, as above provided, this award shall become due, no discovery in physical or astronomical science, or no new application of scientific principles to useful purposes, has been made worthy of the distinction proposed, then it is my wish and request the award shall be for that time omitted.