# And finally… the Astronomy!

Allegory of the Astronomy
Laurent de la Hire
Musée des Beaux-Arts (Orleans)

The third mathematical chapter of the De la Hire’s Liberal Arts is the Astronomy. We can see in the painting a lot of astronomical instruments and books!

Location: Musée des Beaux-Arts (map)

# De la Hire’s Geometry

Allegory of the Geometry
Laurent de la Hire

De la Hire also painted the allegories of the Geometry and the Astronomy. The Geometry is  a young woman with a paper in her left hand in which we can see some geometrical constructions as the famous Euclid’s demonstration of the theorem of Pythagoras:

Detail of the painting

In her left hand, she also holds a right angle edge and a compass. We can also see that there is a sphinx and an Egyptian background in the right which represents the Egyptian origin of the Geometry. Proclus stated that:

Since, then, we have to consider the beginnings of the arts and sciences with reference to the particular cycle [of the series postulated by Aristotle] through which the universe is at present passing, we say that, according to most accounts, geometry was first discovered in Egypt, having had its origin in the measurement of areas. For this was a necessity for the Egyptians owing to the rising of the Nile which effaced the proper boundaries of everybody’s lands.

Herodotus says that Ramses II distributed the land among the Egyptians in equal rectangular plots on which he levied an annual tax. When therefore the river swept away a portion of a plot and the owner applied for a corresponding reduction in the tax, surveyors had to sent down to certify what the reduction of the area had been.

The Geometry is next to a globe which nods to the science devoted o measuring the Earth (Geo + metry = Earth + measurement). There is also a snake representing the ancient goddess of the Earth.

Location: The Toledo Art Museum (map)

# De la Hire’s Arithmetic

Laurent de la Hyre’s Arithmetic
Walters Arts Museum (Baltimore)
Source: Wikimedia Commons

Today is March 18, 2013 and Philippe de la Hire was born on March 18, 1640. Philippe de la Hire was a French mathematician who worked on astronomy and the conic sections. He provided an exposition of the properties of the conic sections and he applied the analytic geometry to some indeterminate problems about intersection of curves.

Philippe de la Hire’s father was the painter Laurent de la Hire (1606-1656) who got a lot of commissions from distinguished politicians, the Church and rich Parisian who wanted to have a portrait in their houses. But Laurent de la Hire had also time to paint the Allegories of the Liberal Arts and the Arithmetic can be enjoyed in the Walters Arts Museum of Baltimore.

Detail of the picture

The Arithmetic holds a book in which we can read the name of Pythagoras (c. 570 aC – c. 495 aC) and there is a paper on the book with the words “par” (“even”) and “impar” (“odd”) and an addition,  difference and a multiplication. Can you imagine the young Philippe watching his father painting this picture? Maybe Philippe found his way to Mathematics in that moment!

Location: The Walters Art Museum (map)