LIVINGSTON PLATT TO WED.Grandson of Senator Platt Is Engr/ged to Miss Agnes Booth.Special to The Nezv York Times.CHICAGO, Dec. 28.—Mr. and Mrs. Vernon Booth announce the engagement of their daughter Agnes to Livingston Platt, son of Mr. and Mrs. Frank H. Platt of New York, and grandson of Senator Platt. Mr. Platt is a student in his lather’s law office. The announcement was made to the family and friends at theChristmas house party for which Mr. and Mrs. P. A. Valentine came on from New York and opened up Danforth Lodge, their Oconomowoc home.Miss Booth is a favorite niece of Mrs. Valentine, and since her coming oat two or three years ago has been made the centre of most of the Danforth Lodge festivitf.es. Mr. Platt came from New York to be a member of the family house party, and to-night Mr. and Mrs. Valentine gave a large dinner company in honor of the betrothed couple. Mr. P. D. Armour went to Oconomowoc yesterday to be among the guests.No date is set for the wedding.