“The speed of a rocket, Don, wouldn’t do you very much good while flying over the fighting front,” replied his chum, rather grimly.

Don, too impatient, too restless to remain much longer indoors, soon started off with the other at his side. And all the while the obliging artisan kept imparting interesting bits of information. He told them something about the giant bi-motored Caudron, the Handley-Page and the Caproni, each type of machine representing the highest achievement in airplane building by the respective countries of France, England and Italy.

“The Boches,” he added, with a scowl, “have the Gothas.”

“I remember reading that some of the Gothas which bombed London had a wing-spread of seventy-eight feet, with motors of two hundred and sixty horse power, and carried, besides three men, hundreds of pounds of explosives,” remarked Don.

“Seventy-eight feet is nothing these days,” commented the Frenchman, musingly. “A hundred and fifty is more like it. You and I, mes Americaines, will live to see the time when huge flyers, with comfortable accommodations for passengers, can cross the Atlantic, linking still closer the old world and the new.”

Their volunteer guide now conducted the boys to another department, where they saw many women engaged in sewing together breadths of fine linen cloth destined to be stretched over the skeleton frames.

“Billions have been spent and are being expended in the airplane industry,” continued the man. “Even piano and furniture factories and many others have turned their attention to the fabrication of airplane parts, such as struts, ribs and propellers. And all this, in connection with aeronautic machinery, means work for thousands of mechanics. Vast quantities of raw material are required. Airplanes must be housed: therefore the erection of hangars and other types of buildings will employ thousands more. Then, the training of aviators, too, is a pretty expensive operation.”

“I suppose so,” laughed Don. “However, I’ll try to let ’em down as easily as I can. Coming, George?”

After heartily thanking the obliging artisan for his courtesy the two left the busy shops.

By this time the slowly-rising sun was casting its first pale and delicate tints over the earth. And with these rays the gloom which had taken possession of nature for so many hours began to lift. The dull and lifeless landscape, freed from the embracing mists, took on an aspect of quiet beauty and charm, and drops of dew shone and sparkled like “many a gem of purest ray serene.”