The measure of time passing
Before the invention of the mechanical clock, two kinds of instruments were used to measure time. On the one hand, hourglasses and water clocks, were used to count the passage of time, the time that is ‘running’. On the other, gnomons and sundials give this hour, the hour of the stars.
One of the most famous nude paintings due to its erotic charge is little known to have suffered slashing by suffragette almost 100 year ago. More details about the destructive event could be found at: http://www.bbc.co.uk/news/blogs-magazine-monitor-26491421