3. There are innumerable other paths of practical continuity among things. Lines of INFLUENCE can be traced by which they together. Following any such line you pass from one thing to another till you may have covered a good part of the universe's extent. Gravity and heat-conduction are such all-uniting influences, so far as the physical world goes. Electric, luminous and chemical influences follow similar lines of influence. But opaque and inert bodies interrupt the continuity here, so that you have to step round them, or change your mode of progress if you wish to get farther on that day. Practically, you have then lost your universe's unity, SO FAR AS IT WAS CONSTITUTED BY THOSE FIRST LINES OF INFLUENCE. There are innumerable kinds of connexion that special things have with other special things; and the ENSEMBLE of any one of these connexions forms one sort of system by which things are conjoined. Thus men are conjoined in a vast network of ACQUAINTANCESHIP. Brown knows Jones, Jones knows Robinson, etc.; and BY CHOOSING YOUR FARTHER INTERMEDIARIES RIGHTLY you may carry a message from Jones to the Empress of China, or the Chief of the African Pigmies, or to anyone else in the inhabited world. But you are stopped short, as by a non-conductor, when you choose one man wrong in this experiment. What may be called love-systems are grafted on the acquaintance-system. A loves (or hates) B; B loves (or hates) C, etc. But these systems are smaller than the great acquaintance-system that they presuppose.