Between the vigil office and the dawn office there was in the long winter nights there was an interval, which "should be spent in study by those who need a better knowledge of the Psalter or the lessons"; in the summer nights the interval was short, only enough for the monks to "go out for the necessities of nature". The vigil office was also shortened in the summer months by replacing readings with a passage of scripture recited by heart, but keeping the same number of psalms. Both in summer and in winter the vigil office was longer than on other days, with more reading and the recitation of canticles in addition to the psalms.