exactly in his autograph, and with every peculiarity, blot, or erasure, at the nearest office.  Here the copy is placed in the proper box, and at once reproduced in the office nearest the residence of the person to whom it is addressed, and forwarded in the same manner to him.  A letter, therefore, covering one of these slips, and saying as much as we could write in an average hand upon a large sheet of letter-paper, is delivered within five minutes at most from the time of despatch, no matter how great the distance.

I remarked that this method of communication made privacy impossible.

“But,” replied the official, “how could we possibly have time to indulge in curiosity?  We have to sort hundreds of these papers in an hour.  We have just time to look at the address, place them in the proper box, and touch the spring which sets the electric current at work.  If secrecy were needed a cipher would easily secure it, for you will observe that by this telegraph whatever is inscribed on the sheet is mechanically reproduced; and it would be as easy to send a picture as a message.”

I learnt that a post of marvellous perfection had, some thousand years ago, delivered letters all over Mars, but it was now employed only for the delivery of parcels.  Perhaps half the commerce of Mars, except that in metals and agricultural produce, depends on this post.  Purchasers of standard articles describe by the telegraph-letter to a tradesman the exact amount and pattern of the goods required, and these are despatched at once; a system of banking, very completely organised, enabling the buyer to pay at once by a telegraphic order.

When Esmo had finished his business, we walked down, at my request, to the port.  Around three sides of the dock formed by walls, said to be fifty feet in depth and twenty in thickness, ran a road close to the water’s edge, beyond which was again a vast continuous warehouse.  The inner side was reserved for passenger vessels, and everywhere the largest ships could come up close, landing either passengers or cargo without even the intervention of a plank.  The appearance of the ships is very unlike that of Terrestrial vessels.  They have no masts or rigging, are constructed of the zorinta, which in Mars serves much more effectively all the uses of iron, and differ entirely in construction as they are intended for cargo or for travel.  Mercantile ships are in shape much like the finest American clippers, but with broad, flat keel and deck, and with a hold from fifteen to twenty feet in depth.  Like Malayan vessels, they have attached by strong bars an external beam about fifty feet from the side, which renders overturning almost impossible.  Passenger ships more resemble the form of a fish, but are alike at both ends.  Six men working in pairs four hours at a time compose the entire crew of the largest ship, and half this number are required for the smallest that undertakes a voyage of more than twelve hours.