Figure 5. The thermally equalized helmets were then placed on a sheet of plywood on the ground in full sunlight. The standard helmet is on the left and the drop liner helmet is on the right in both images. Being around midday and only 4o south of the equator the solar radiation was ample for the purpose. After 10 minutes the helmets were quickly taken and placed on their sides in the shade and thermal images taken of their interiors. It can be seen that now the centre of the bowl in the standard Wolseley is 40.3oC (104.5oF) and the same spot in the centre of the ‘drop liner’ helmet is 35.9oC (96.6oF), with the relatively cool (blue) circular area of the foil liner clearly seen.