Its first and most signal advantage consists in the truly electrical celerity with which it transmits intelligence and communications through the greatest distances. It supplies, with a perfection like magic, the first and most important and difficult _desideratum_ in a post office establishment—especially in one which has to serve a country so vast as ours. That desideratum is despatch—rapidity of transmission. It is to secure this, that the government pays a hugely greater price for the carrying and delivery of the mails, than any other equal _quantum_ of transportation costs in the world. Nature seemed to have fixed certain limits to the speed of transmission, which it seemed impossible to pass; and those limits appeared to be reached by the steam-engine. But they have been utterly transcended by the electro magnetic telegraph, which has literally demolished time and space for all purposes of correspondence between places connected by its wonder-working wires. Another inestimably important advantage of Professor Morse’s telegraph consists in the fulness, precision, and variety of matter which it is capable of communicating. Its alphabet contains representatives of all the letters of our language, and of all the numerals of arithmetic; and they are capable of infinite combination and repetition under the magnetic impulse. Hence it is obvious that the _capacity_ of the instrument is competent to the communication of a long discourse of the greatest variety of thought and expression. But, as the telegraph letters must necessarily be despatched along the wire, and marked down, one by one, at the station to which they are transmitted, it is obvious that a long discourse must occupy considerable time, although the letters follow each other in the most rapid succession.