After a small number of beats our impression of the amount we have told off becomes quite vague. Our only way of knowing it accurately is by counting, or noticing the clock, or through some other symbolic conception. When the times exceed hours or days, the conception is absolutely symbolic. We think of the amount we mean either solely as a _name_, or by running over a few salient _dates_ therein, with no pretence of imagining the full durations that lie between them. No one has anything like a _perception_ of the greater length of the time between now and the first century than of that between now and the tenth. To an historian, it is true, the longer interval will suggest a host of additional dates and events, and so appear a more _multitudinous_ thing. And for the same reason most people will think they directly perceive the length of the past fortnight to exceed that of the past week. But there is properly no comparative time-_intuition_ in these cases at all. It is but dates and events representing time, their abundance symbolizing its length. I am sure that this is so, even where the times compared are no more than an hour or so in length. It is the same with spaces of many miles, which we always compare with each other by the numbers that measure them. From this we pass naturally to speak of certain familiar variations in our estimation of lengths of time. _In general, a time filled with varied and interesting experiences seems short in passing, but long as we look back. On the other hand, a tract of time empty of experiences seems long in passing, but in retrospect short._ A week of travel and sight-seeing may subtend an angle more like three weeks in the memory; and a month of sickness yields hardly more memories than a day. The length in retrospect depends obviously on the multitudinousness of the memories which the time affords. Many objects, events, changes, many subdivisions, immediately widen the view as we look back. Emptiness, monotony, familiarity, make it shrivel up. _The same space of time seems shorter as we grow older_--that is, the days, the months, and the years do so; whether the hours do so is doubtful, and the minutes and seconds to all appearance remain about the same. An old man probably does not _feel_ his past life to be any longer than he did when he was a boy, though it may be a dozen times as long. In most men all the events of manhood's years are of such familiar _sorts_ that the individual impressions do not last. At the same time more and more of the earlier events get forgotten, the result being that no greater multitude of distinct objects remains in the memory.