This photograph shows the Boeing-developed shadow compass installed in the astrodome of a Flying Fortress (on top of the fuselage). Modern scientists have made the greatest improvements in the magnetic compass during this war than ever have been made since the compass was devised some 4,000 years ago. But the age-old theory of the sun dial has been applied in the shadow compass to check the variations of the magnetic compass. No outside infuences affect the shadow compass. The dark area surrounding the astrodome is one of the six areas on a Flying Fortress now painted. These spots are painted to keep the glare of the sun from the eyes of the pilots and gunners.