Buffalo, N. ¥., Dec. 16—(UP) The post-war future of America is potentially the greatest period of Prosperity ever known to this na tion. Melvin H. Baker, National Gypsum company president, said today, warning at the same time that the opportunity can be lost unless the job Planning is placed in proper hands. Baker, a member of the post war planning committee of the National Association of Manufac turers, declared that the project should be guided by sound think ing realists who can Pattern a program geared to meet human behaviors. Asserting that the American people will have the necessary buying power, skill and plants in which to produce and meet bost-war demands of this coun try and the entire world, he cau tioned that ‘planning for these op portunities is no job for the theor ists.” ‘As opposed to natural rubber, thiokal will set check, crack or crumble with aging and expo sure to air and sunlight. —Advertising pays both buyer and seller,