Pressed himself as adverse to carrying out the provisions of the merchant marine act of 1920, that commercial treaties preventing the United States from instituting preferential freights be abrogated. President Coolidge expressed himself as adverse to re-enactments. The suggestions made by President Coolidge were renewed. Lloyd George, at Chicago, was arrested today in a government airplane. Secretary of Labor Davis, who stopped off in a government airplane today for Chicago to Berlin, took the airplane. A mob attempted to force its way into the Berlin dock exchange today, but the police appeared more of the situation, after fierce fighting, in which a number were injured, several seriously. The city hall and stock exchange were locked and strongly guarded and Wilhelmstrasse was closed. The meeting of Lloyd George, former British premier, was held today. This was his second attempt to leave by airplane, the first being stopped by a heavy fog. Investigate Grain Rates Washington—(A. P.)—In the investigation instituted by the interstate commerce commission to determine whether the present grain rates are justifiable, the commission also announced its decision in the proceedings instituted by a western state, to secure a reduction in grain rates west of the Mississippi, declaring that the evidence presented was an insufficient reason to put the decreases into force. The commission ordered the record in the western state's complaints reopened and the proceedings retried. Confesses Killing Policeman San Bernardino—(A. P.)—Robert F. Saunders, 20, one of three youths, was arrested today by police.  Arrested yesterday while driving the car of Patrolman D. H. Crowther, found shot, Sunday near the Jordan river, Utah, confessed killing the policeman, according to a statement from the sheriff's office. 