Still, in spite of all this general agreement, men are kept apart who might come together; or, in some cases, a passing discord springs up between them. This is due to diversity of mood. You will hardly ever see two people exactly in the same frame of mind; for that is something which varies with their condition of life, occupation, surroundings, health, the train of thought they are in at the moment, and so on. These differences give rise to discord between persons of the most harmonious disposition. To correct the balance properly, so as to remove the disturbance--to introduce, as it were, a uniform temperature,--is a work demanding a very high degree of culture. The extent to which uniformity of mood is productive of good-fellowship may be measured by its effects upon a large company. When, for instance, a great many people are gathered together and presented with some objective interest which works upon all alike and influences them in a similar way, no matter what it be--a common danger or hope, some great news, a spectacle, a play, a piece of music, or anything of that kind--you will find them roused to a mutual expression of thought, and a display of sincere interest. There will be a general feeling of pleasure amongst them; for that which attracts their attention produces a unity of mood by overpowering all private and personal interests. And in default of some objective interest of the kind I have mentioned, recourse is usually had to something subjective. A bottle of wine is not an uncommon means of introducing a mutual feeling of fellowship; and even tea and coffee are used for a like end. The discord which so easily finds its way into all society as an effect of the different moods in which people happen to be for the moment, also in part explains why it is that memory always idealizes, and sometimes almost transfigures, the attitude we have taken up at any period of the past--a change due to our inability to remember all the fleeting influences which disturbed us on any given occasion. Memory is in this respect like the lens of a _camera obscura_: it contracts everything within its range, and so produces a much finer picture than the actual landscape affords. And, in the case of a man, absence always goes some way towards securing this advantageous light; for though the idealizing tendency of the memory requires times to complete its work, it begins it at once. Hence it is a prudent thing to see your friends and acquaintances only at considerable intervals of time; and on meeting them again, you will observe that memory has been at work. SECTION 23. No man can see _over his own height._ Let me explain what I mean.