Taken from the frontispiece of the second edition of the Encyclopedia Britannica, c 1788. © SSPL/Getty Images
1768 - Encyclopaedia Britannica first published
The first edition of the Encyclopaedia Britannica is published in Edinburgh, Scotland as three volumes, between 1768 and 1771. The first edition of the encyclopaedia was described as 'A Dictionary of Arts and Sciences, compiled upon a New Plan'. It is now the oldest English-language encyclopaedia still in publication.
1850 - Hermann von Helmholtz invents the ophthalmoscope
German doctor Hermann von Helmholtz invents the ophthalmoscope, an instrument used to observe the eye during a medical exam. His invention revolutionised ophthalmoscopy, and helped uncover the mysteries of what lies behind the eye. He invented the instrument to help explain to his students why the pupil of an eye sometimes appears light.
2006 - NASA releases photos of flowing water on Mars
NASA releases images that indicate water has recently flowed on the surface of Mars. Life requires flowing, liquid water to survive, therefore the two photos, taken six years apart could provide evidence that life may have at one point existed on the Red Planet.
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