All inventions:

http://inventors.about.com/library/bl/bl12.htm

www.cbc4kids.ca/general/the-lab/history-of-invention/default.html

Invention of paper:

http://www.wipapercouncil.org/invention.htm

Invention of soap:

http://www.smith.edu/hsc/museum/ancient_inventions/hsclist.htm

The wheel and ancient calendar:

http://library.thinkquest.org/C004203/science/science02.htm

Bow and arrow:

http://www.bartleby.com/65/bo/bowNarro.html

Windmill:

http://www.education.eth.net/enrich/inventions/ccorner_invention3.htm