As connected with objects, it is colour; and the sun is its deity. The fourth should be known as Water. As connected with the soul, it is said to be the tongue.
अधिभूतं ततो रूपं सूर्यस्तत्राधिदैवतम्। चतुर्थमापो विज्ञेयं जिह्वा चाध्यात्ममुच्यते॥