Machinery 15 Agricultural machinery 13 Machinery industry 12 Harvesting machinery 9 History 7 Machinery in the workplace 7 Refrigeration and refrigerating machinery 5 more ... Woodworking machinery 5 Defense industry 4 Exhibitions 4 Lumber trade 4 Agriculture 3 Building materials industry 3 Employment 3 Equipment and supplies 3 Patents--Machinery--19th century 3 Pumping machinery 3 Streets 3 Textile industry 3 Women 3 Woodworkers 3 Woodworking industries 3 African Americans 2 Chains 2 Coke industry 2 Construction industry 2 Conveying machinery 2 Economic aspects 2 Economic conditions 2 Hoisting machinery 2 Labor and laboring classes 2 Labor productivity 2 Machine-tool industry 2 Machines de récolte 2 Milling machinery 2 Office buildings 2 Papermaking machinery 2 Patent suits 2 Petroleum industry 2 Railroad stations 2 less ...