2009-01-222009-01-221903-08Indiana State Board of Health. Monthly Bulletin. 1903; 5(8) :90.0019-6754https://hdl.handle.net/1805/1764[Chalkboard erasers before and after, using Chalk dust cleaner]Fujitsu fi-4220c2, Adobe Photoshop CS3, 966 KBPage 90, lower left approximately 5 X 2 in.Photograph in periodical.JPEGen-usAlthough these works may be freely accessible on the World Wide Web and may not include any statement about copyright, the U.S. Copyright Act nevertheless provides that such works are protected by copyright. Users must assume that works are protected by copyright until they learn otherwise.ErasersIndianaChalkDustInventionsJones, J.A.(Plymouth)SchoolsSimple MachinesImage