Hermann Diels popularized the term pre-socratic in Die Fragmente der Vorsokratiker (The Fragments of the Pre-Socratics) in 1903. However, the term pre-Sokratic was in use as early as George Grote's Plato and the Other Companions of Sokrates in 1865.
The cost of a solar panel today is around $3 per watt, and the extra cost of installation brings costs up to $5- $6 per watt. Note: Installation costs for PV systems include both labor and the electronics needed to tie the solar array into your existing electrical system.
Solar panels are currently selling for as low as US$0.70 per watt (7-April-2012) in industrial quantities; the balance of system costs (inverters, racks, wiring, marketing) made the median price in 2011 of large (>100 kW) systems $2.60/watt in Germany and $4.87/watt in the US.