GETTING MY HWGACOR TO WORK

" An experiment by using a drinking water-filled glass sphere was carried out and al-Farisi showed the additional refractions due to the glass could be overlooked in his design.[74][c] As he pointed out in his Kitab Tanqih al-Manazir (The Revision with the Optics), al-Farisi utilised a big very clear vessel of glass in The form of a sphere, which w