The widow of J. C. Loudon, the eminent botanical writer and landscape and architectural gardener, died in the second week of July last, leaving a place vacant in society and letters. Thirty years ago - then Miss Webb - she made her first appearance in print, in a remarkable novel called "The Mummy," which won for her not only public applause, but the hand of J. C. Loudon. In Mr. Loudon's works, she bore a share; and on her own separate account has produced a number of beautiful and important books, well known in every lady's library, and one of which was thought worthy of being edited by our own Downing.

Dawson Turner has also paid the debt of nature. He was distinguished in early life for his botanical studies, and afterwards for his antiquarian knowledge. He and Robert Brown - long united by friendship - expired within one week of each other. Turner, at the age of 73.

Aime Bonpland, the veteran naturalist, has also been numbered among the dead, at the age of 85, at Montevideo.

Agricultural Exhibitions for the year 1858.

Alabama, Montgomery, Oct. 18 to 22. California, Marysville, Aug. 23 to 27. Connecticut, Hartford, Oct. 12 to 15. Georgia, Atlanta, Oct. 10 to 23. Illinois, Centralia, Sept. 14 to 17. Indiana, Indianapolis, Oct. 4 to 9. Iowa, Oscaloosa, Sept. 28 to Oct. 1. Kentucky, Louisville, Oct. 5 to 8. Maine, Augusta, Sept. 21 to 24. Maryland, Baltimore, Oct. 19 to 22. Michigan, Detroit, Sept. 28 to Oct. 1. Missouri, St. Louis, Sept. 6 to 11. New Hampshire, Dover, Oct. 6 to 8. New Jersey, Trenton, Sept. 14 to 17.

New York, Syracuse, Oct. 5 to 8. North Caroliua, Raleigh, Nov. 2 to 6. Ohio, Sandusky, Sept. 15 to 19. Pennsylvania, Pittsburg, Sept. 28 to Oct. 1. Rhode Island, Providence, Sept 28 to Oct. 1. South Carolina, Columbia, Nov. 9 to 12. Vermont, Burlington, Sept. 14 to 17. Virginia, Petersburg, Nov 2 to 6. Wisconsin, Madison, Oct. 4 to 9. United States, Richmond, Va., Oct 25 to 30. Horse Exhibition, Springfield, Mass., Sept. 14 to 17. Canada East, Montreal, Sept 28 to Oct. 1. Canada West, Toronto, Sept. 28 to Oct. 1.

The American Agriculturist is now also printed in German, and no doubt to advantage of reader and publisher. We should prefer it in its English dress, but no doubt it reads " all the same in Dutch" to those who understand it.

Mr. Editor, - At a special meeting of the Horticultural Society Of Morrisania, the following officers were elected for the ensuing year:

President, Samuel Munn. Vice Presidents, Win. W. Fox, Robt. H. Elton, L. R. Osborn, Carp. Moger, Thos. W. Ball, H. M. Morris, Thos. E. Sutton, Francis I. Smith, Benj. D. Whit-lock, Adrian James, F. W. Gilley, Lewis G. Morris, David Milliken, G. W. Alexander, Jas. Garner, Andrew Richardson, Jordan L. Mott, Jr., F. Grote. Secretary, William H. Wilcox. Treasurer, Jas. L. Parshall. Librarian, James Stillman.

It was decided to hold an exhibition in the village of Morrisania on Wednesday and Thursday the 6th and 7th of October next, and Messrs. Samuel Munn, Wm. H. Wilcox, Geo. H. Pollock, Thos. E. Sutton, H. P. Sandford, G. W. Alexander, and Gilbert Dayton, were appointed a Committee of Arrangements for the same.

Respectfully yours, Wm. H. Wilcox, Secretary.

Morrisania, August 9,1858.