The science which existed in the ancient Vedas was the science of the elements: fire, earth, water, air, ether. But these words should not be taken as meaning the same as in everyday language. The element of water, for instance, signifies the liquid state, fire signifies heat or warmth. Through this science the Hindus were able to construct Ragas or modes to be sung or played at a certain time of the day or night, or at a certain season. After these songs have been sung for thousands of years, the race has developed such a sense of appreciation of these Ragas, that even an ordinary man in the street cannot bear to hear a Raga of the morning sung in the evening. He may not know the form or the notes, but to his ears it sounds disagreeable; he cannot stand it. We may say it is a matter of habit - and that is true - but I have made experiments with different Ragas, and found that a mode that should be sung in the middle of the night loses its beautiful influence if we sing it at noon.