Our experience is, literally and exactly, a series or sequence--a flux or stream. It is composed of objects or of groups, according to the width of our attention. If we travel over a large tract of country the experience is a train of objects or views, which follow each other continuously but for interruptions in attention. If we were bound to think of things in the order in which they were experienced, we should have to imagine our topographical consciousness as a long ribbon of views, like the pictures of a panorama. Supposing we travelled hither and thither over one county, it would appear to us as a straight strip of land which might be several hundred miles long. If we again traversed the ground, but in another order, we should have another strip resembling the first, but also differing from it, and it would be necessary to keep the two from being confused in our mind. If several persons traversed the same ground but in divers directions, they would each retain a different recollection of it, and it would be extremely hard for any two of them to agree as to the order in succession of any portion of the ground traversed. Our experience of the natural group suggests a mode of treating our geographical experience which overcomes many of these inconveniences. We find that we can traverse (either bodily or by the eye) a single landscape in a thousand directions, and retain a memory of it without any reference to these directions. What we remember is the mutual positions of the objects, not the order in which they were observed. As this greatly facilitates the memory of one group, we apply the same principle of synthesis to the succession of groups composing our geographical experience. We dismiss from our minds the order of observation, and construct instead an imaginary group of associated objects or places having mutual positions. It is imaginary, for no one has ever seen as a co-existent synthesis the objects of a county, not to speak of a country or continent. Substituting for memory of succession, a memory of position, there grows up in our mind a large co-existent image of a country on the model of a single group, which affords all the advantages as regards economy of energy which we enjoy by virtue of comprehending a natural group in one act of consciousness.