Marsh, James E., Roxbury, Mass. (10).
Mather, William W., Columbus, Ohio (1).
Maupin, S., Charlottesville, Va. (10).
McMahon, Mathew, Albany, N. Y. (11).
M'Conihe, Isaac, Troy, N. Y. (4).

Meade, George G., Philadelphia, Pa. (15).
Meek, F. B., Washington, D. C. (6).
Mitchell, O. M., Cincinnati, Ohio (3).

Mitchell, William, Poughkeepsie, N. Y. (2).
Mitchell, Wm. H., Florence, Ala. (17).
Morton, S. G., Philadelphia, Pa. (1).
Munroe, Nathan, Bradford, Mass. (6).

Newton, E. H., Cambridge, N. Y. (1).
Nicollett, J. N., Washington, D. C. (1).
Norton, J. P., New Haven, Conn. (1).
Noyes, J. O., New Orleans, La. (21).
Nutt, Cyrus, Bloomington, Ind. (20).

Oakes, William, Ipswich, Mass. (1).

Olmsted, Alexander F., New Haven, Conn. (4). Olmsted, Denison, New Haven, Conn. (1).

Olmsted, Denison, jr., New Haven, Conn. (1).

Painter, Jacob, Lima, Pa. (23).

Painter, Minshall, Lima, Pa. (7).

Parkman, Samuel, Boston, Mass. (1).

Perkins, George R., Utica, N. Y. (1).

Perkins, Henry C., Newburyport, Mass. (18).

Perry, John B., Cambridge, Mass. (16).

Perry, M. C., New York (10).

Piggot, A. Snowden, Baltimore, Md. (10).

Plumb, Ovid, Salisbury, Conn. (9).

Pope, Charles A., St. Louis, Mo. (12).

Porter, John A., New Haven, Conn. (14).

Pugh, Evan, Centre Co., Penn. (14).

Redfield, William C., New York (1).
Resor, Jacob, Cincinnati, Ohio (8).
Robb, James, Fredericton, N. B. (4).
Robinson, Coleman T., Buffalo, N. Y. (15).
Rockwell, John A., Norwich, Conn. (10).
Rogers, Henry D., Glasgow, Scotland (1).
Rogers, James B., Philadelphia, Pa. (1).

Schaeffer, Geo. C., Washington, D. C. (1). Scott, Joseph, Dunham, C. E. (11). Senter, Harvey S., Aledo, Ill. (20). Seward, William H., Auburn, N. Y. (1). Sherwin, Thomas, Dedham, Mass. (11). Silliman, Benjamin, New Haven, Conn. (1). Skinner, John B., Buffalo, N. Y. (15). Slack, J. H., Philadelphia, Pa. (12). Smith, J. V., Cincinnati, Ohio (5). Smith, James Y., Providence, R. I. (9). Smith, Lyndon A., Newark, N. J. (9). Sparks, Jared, Cambridge, Mass. (2). Stimpson, William, Chicago, Ill. (12). Stone, Samuel, Chicago, Ill. (17). Sullivant, W. S., Columbus, Ohio (7).

Tallmadge, James, New York (1).
Taylor, Richard C., Philadelphia, Pa. (1).
Teschemacher, J. E., Boston, Mass. (1).
Thompson, Alexander, Aurora, N. Y. (6).
Thompson, Z., Burlington, Vt. (1).
Thurber, Isaac, Providence, R. I. (9).
Tillman, Samuel D., Jersey City, N. J. (15).
Tolderoy, James B., Fredericton, N. B. (11).
Torrey, John, New York (1).

Torrey, Joseph, Burlington, Vt. (2).
Totten, J. G., Washington, D. C. (1).
Townsend, Howard, Albany, N. Y. (10).
Townsend, John K., Philadelphia, Pa. (1).
Townsend, Robert, Albany, N. Y. (9).
Troost, Gerard, Nashville, Tenn. (1).
Tuomey, M., Tuscaloosa, Ala. (1).
Tyler, Edward R., New Haven, Conn. (1).

Van cleve, John W., Dayton, Ohio (1).
Vanuxem, Lardner, Bristol, Pa. (1).

Wadsworth, James S., Genesee, N. Y. (2).
Wagner, Tobias, Philadelphia, Pa. (9).
Walker, Joseph, Oxford, N. Y. (10).

Walker, Sears C., Washington, D. C. (1).
Walker, Timothy, Cincinnati, Ohio (4).
Walsh, Benjamin D., Rock Island, Ill. (17).
Warren, John C., Boston, Mass. (1).
Webster, H. B., Albany, N. Y. (1).
Webster, J. W., Cambridge, Mass. (1).

Webster, M. H., Albany, N. Y. (1).

Weed, Monroe, Wyoming, N. Y. (6).
Weyman, G. W., Pittsburg, Pa. (6).
Wheatland, Richard H., Salem, Mass. (13).
Whitman, Wm. E., Philadelphia, Pa. (23).
Whitney, Asa,, Philadelphia, Pa. (1).
Whittlesey, Charles C., St. Louis, Mo. (11).
Willard, Emma, Troy, N. Y. (15).
Wilson, W. C., Carlisle, Pa. (12).

Winlock, Joseph, Cambridge, Mass. (5).
Woodbury, L., Portsmouth, N. H. (1).
Woodman, John S., Hanover, N. H. (11).
Wright, John, Troy, N. Y. (1).

Wyman, Jeffries, Cambridge, Mass. (1).

Young, Ira, Hanover, N. H. (7).

[256 DECEASED Members,]

GENTLEMEN AND LADIES OF THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE:

IN availing myself of the privilege accorded by the custom of the Association to its President of the preceding year, of making a general address, I cannot but feel a strong temptation, under the influence of the Centennial year of the Republic, to attempt a general review of the progress of science during the past century. The genius of the year is that of retrospective contemplation, of comparison of the past with the present, not unaccompanied with a justifiable sense of satisfaction at the evidences of real advance.

Much has been said and written on the progress of the nation in polity, in wealth, in the arts, and in science. The Centennial reviews, published in several of the leading popular periodicals, have sketched with more or less detail the history of scientific development in this country, but there still seems to remain room for a philosophic appreciation of the change that has been wrought in the dominant modes of thought in the different branches of human knowledge. The occasion invites the attempt to trace critically the steps by which the science of pure mathematics,

having perhaps exhausted the methods within the range of the material world, has sought a new field of activity in investigating the properties of magnitudes inconceivable to the human mind as at present constituted, such as space of five dimensions, while the application of the previously developed mathematical modes of thought to the problems of the forces of nature has immensely aided the appropriation of those forces to the practical uses of man to follow the influence which the principle of the conservation of force, recognized ages ago in the philosophic axiom that cause and effect are equivalent, but a hundred years ago still standing applied only to the doctrine of mass-motion, has exercised upon modern modes of thought, as the basis of the correlation of forces, the fruitful principle by which all phenomena of molecular force, light, heat, electricity, galvanism and magnetism,-are reduced to the common idea of some mode of motion, convertible one with another and with mass-motion:

In Chemistry, to show how the same fundamental idea has led us from the crude conceptions of phlogiston and anti-phlogiston, of free and latent Caloric, to the acceptance of the energy of molecular motion as the condition of chemical combinations, or, as we should now say, the association or dissociation of different molecules:

In Geology, to illustrate how vague notions of cataclysms, upheavals and submergences, imagined to explain observed phenomena, but without assignable cause, have, under the influence of the same potent demand for balancing the debit and credit account of the forces invoked, given way to the research and discrimination of effects of recognized and enduring causes, acting slowly but ceaselessly; so slowly that the astronomical evidence of cosmical changes has been called in to account for even that very recent and superficial change, the glacial period :

To contrast, further, in the study of organic nature, the crude categories formed an hundred years ago on external resemblances with the classifications of to-day, based upon the most careful observation of genetic differences: and, last in logical sequence, but of the first importance in our day, to appreciate philosophically the progress in the doctrine of evolution, as it is called by its votaries, or the natural history of creation as may be better understood by many of my hearers-these subjects present themselves forcibly to my mind.