With the war ended, all the Allied powers have large numbers of airplanes on their hands and also large numbers of trained aviators. Undoubtedly airplanes will continue to fill the skies in Europe and we shall see more and more of them in this country. Even during the war they were used for other purposes than fighting. There were ambulances on wings--machines with the top of the fuselage removable so that a patient on a stretcher could be placed inside. A French machine was furnished with a complete hospital equipment for emergency treatment and even for performing an operation in case of necessity. The flying hospital could carry the patient back to the field or base hospital after treatment. Mail-carrying airplanes are already an old story. In Europe the big bombing-machines are being used for passenger service between cities. There is an air line between Paris and London. The airplanes carry from a dozen to as many as fifty passengers on a single trip. In some cities here, as well as abroad, the police are being trained to fly, so that they can police the heavens when the public takes to wings. Evidently the flying-era is here. CHAPTER VIII SHIPS THAT SAIL THE SKIES Shortly after the Civil War broke out, Thaddeus S. C. Lowe, an enthusiastic American aëronaut, conceived the idea of sending up scout balloons to reconnoiter the position of the enemy. These balloons were to be connected by telegraph wires with the ground, so that they could direct the artillery fire. The idea was so novel to the military authorities of that day that it was not received with favor. Balloons were looked upon as freak inventions, entirely impracticable for the stern realities of war; and as for telegraphing from a balloon, no one had ever done that before. [Illustration: (C) Underwood & Underwood A big German Zeppelin that was forced to come down on French soil] But this enthusiast was not to be daunted, and he made a direct appeal to President Lincoln, offering to prove the practicability of this means of scouting. So he took his balloon to Washington and made an ascent from the grounds of the Smithsonian Institution, while the President came out on the lawn south of the White House to watch the demonstration. In order to test him, Mr. Lincoln took off his hat, waved his handkerchief, and made other signals. Lowe observed each act through his field-glasses and reported it to the President by telegraph. Mr. Lincoln was so impressed by the demonstration that he ordered the army to use the observation balloon, and so with some reluctance the gas-bag was introduced into military service, Professor Lowe being made chief aëronautic engineer. Under Lowe's direction the observation balloons played an important part in the operations of the Union Army. [Illustration: Courtesy of "Scientific American" Observation Car lowered from a Zeppelin sailing above the clouds]