4. Pre 1660
• In 11th century , the Arab Alhazan described the use and characteristics of glass lenses
• Roger bacon was familiar with lenses and eye glasses , however weren’t invented until late 1200s
1600s
• 1608 Telescope was invented , with Galileo improving upon it with his own models
• Around 1600 microscope was invented possibly by Hans and Zacharias Jansen. But lens quality was poor
• FIRST BIG MICROSCOPE: came in 1665 when Robert hook published the MICROGRAPHIA
Late
1660s
• Antony began to grind his own lens and make simple microscope . He discovered nematode and rotifers
1700-
1800s
• Not much change in basic microscope butt certain problems were resolved n this era like color distortion
and poor image resolution
• Ernst Abbe : oil emersion lense can prevent length distortion .
1900 till
now
• In 1931 German scientist invented electron microscope which can magnify as much as million times .only
draw back is living cell can not be viewed by using it