The breath is the sound, not that sound that our ears can hear, but a fine sound. You may have read that in former ages there were people who lived for hundreds of years. You may have read that the yogis live for two hundred or three hundred years. This is because of the breath. Mahmud Ghasnavi, the emperor, lived for one hundred and twenty years. In his old age he had learnt mysticism and the science of breath. When the breath is long, the life is long in proportion. It is just like the tick of a clock. If the swing is shortened, then the clock will finish the twelve hours it has to run in less time. It is so with the length of life. All our life depends upon the breath, its length, shortness, depth.