“I perceive,” said our friend, “from this and other things you have told me, that your development is going on in about the order which has prevailed on Mars. Do not be discouraged in your efforts to bring that mysterious and wonderful agent, electricity, into complete subjection. You will find it your most useful servant, and in connection with aluminum it will enable you to solve numerous problems and remove many difficulties from your path of progress. “Here we have made full use of both of these valuable helps. Electricity enters into every department of life. “It runs our errands, takes us from place to place, builds our houses, cooks our food, and even is applied to the growth of our food when we are in haste for any article. Its laws are so well understood that there is no fear of personal injury from its use, and I will show you how familiar an aid it is to us. Here,” he continued, taking from his pocket a brightly polished case of metal, “is a compact storage battery, containing, not electricity itself, of course, but elements so prepared that a simple touch will start into motion a powerful current, able to perform almost any task I may ask of it. This case, you see, is so small and light that it is no burden, and yet it contains power enough to serve me for many days. Of course, all our work of a fixed character has appliances with the power permanently attached, and these portable reservoirs are carried about with us only for detached and unexpected tasks.” To my experienced eye the doctor’s face looked a little skeptical at this last remark, and he said: “But how can the power be applied in these emergencies? Suppose, for example, it were necessary for you to go from here to the other end of this vessel in half a second, how would the electricity in your box help you do it?” “If I really thought, Doctor, you wanted to be rid of me I would be tempted to try it; but, as I told your companion just now, you had better learn all you can of our history before you begin to see what we can do.