At the question her father laughed.

"See here!" he protested good-humoredly, "what do you think I am? Just because I happen to be a superintendent do you think me a volume of railroad history, young woman? The topic, I confess, is a fascinating one; but I am off for a vacation to-day."

"Oh, tell us, Dad, do!" urged the girl.

"Nonsense! What is the use of spoiling a fine morning like this talking business?" objected her father.

"But it is not business to us," interrupted Mrs. Tolman. "It is simple a story--a sort of fairy tale."

"It is not unlike a fairy tale, that's a fact," reflected her husband gravely. "Imagine yourself back, then, in 1700, before steam power was in use in England. Now you must not suppose that steam had never been heard of, for an ancient Alexandrian record dated 120 B. C. describes a steam turbine, steam fountain, and steam boiler; nevertheless, Hero, the historian who tells us of them, leaves us in doubt as to whether these wonders were actually worked out, or if they were, whether they were anything but miniature models. Still the fact that they are mentioned goes to prove that there were persons in the world who at a very early date vaguely realized the possibilities of steam as a force, whether turned to practical uses or not. For years the subject remained an alluring one which led many a scientist into experiments without number.

In various parts of the world men played with the idea and wrote about it; but no one actually produced any practical steam contrivance until 1650, when the second Marquis of Worcester constructed a steam fountain that could force the water from the moat around his castle as high as the top of one of the towers. The feat was looked upon as a marvel and afterward a larger fountain, similar in principle, was constructed at Vauxhall and from that time on the future of steam as a motive power was a.s.sured."

"Did the Marquis of Worcester go on with his experiments and make other things?" demanded Stephen.

"Apparently not," replied his father. "He did, nevertheless, furnish a basis for others to work on. Scientists were encouraged to investigate with redoubled zeal this strange vapor which, when controlled and directed, could carry water to the top of a castle tower. When in 1698 Savery turned Worcester's crude steam fountain to draining mines and carrying a water supply, every vestige of doubt that this mighty power could be applied to practical uses vanished."

"Did the steam engine come soon afterward?" queried Doris, who had become interested in the story.

"No, not immediately," answered Mr. Tolman, pausing to shift the gear of the car. "Before the steam engine, as we know it, saw the light, there had to be more experimenting and improving of the steam fountain. It was not until 1705 that Thomas Newcomen and his partner, John Calley, invented and patented the first real steam engine. Of course it was not in the least like the engines we use now. Still, it was a steam device with moving parts which would pump water, a tremendous advance over the mechanisms of the past where all the power had been secured by the alternate filling and emptying of a vacuum, or vacant receptacle, attached to the pump. Now, with Newcomen's engine a complete revolution took place. The engine with moving parts, the ancestor of our modern exquisitely constructed machinery, speedily crowded out the primitive steam fountain idea. The new device was very imperfect, there can be no question about that; but just as the steam fountain furnished the inspiration for the engine with moving parts, so this forward step became the working hypothesis for the engines that followed."

"What engines did follow?" Doris persisted, "and who did invent our steam engine?"

"Silly! And you in college," jeered Steve disdainfully.

"I am not taking a course in steam engines there," laughed his sister teasingly. "Anyway, girls are not expected to know who invented all the machines in the world, are they, Dad?"

Mr. Tolman waited a moment, then said soothingly:

"No, dear. Girls are not usually so much interested in scientific subjects as boys are--although why they should not be I never could quite understand. Nevertheless, I think it might be as well for even a girl to know to whom we are indebted for such a significant invention as the steam engine.

"It was James Watt," Stephen a.s.serted triumphantly.

"It certainly was," his father agreed. "And since your brother has his information at his tongue's end, suppose we get him to tell us more about this remarkable person."

Stephen flushed.

"I'm afraid," began he lamely, "that I don't know much more. You see, I studied about him quite a long time ago and I don't remember the details. I should have to look it up. I do recall the name, though--"

His father looked amused.

"I don't know which of you children is the more blameworthy," remarked he in a bantering tone. "Doris, who never heard of Watt; or Stephen, who has forgotten all about him."

Both the boy and the girl chuckled good-humoredly.

"At least I knew his name, Dad--give me credit for that," piped Steve.

"That was something, certainly," Mrs. Tolman declared, joining in the laugh.

"Well, since neither of us can furnish the story, I don't see but that you will have to do it, Dad," Doris said mischievously.

"It would be a terrible humiliation if I should discover that I could not do it, wouldn't it?" replied Mr. Tolman with a smile. "In point of fact, there actually is not a great deal more that it is essential for one to know. It was by perfecting the engines of the Newcomen type and adding to them first one and then another valuable device that Watt finally built up the forerunner of our present-day engine. The progression was a gradual one. Now he would better one part, then some other. He surrounded the cylinder, for example, with a jacket, or chamber, which contained steam at the same pressure as that within the boiler, thereby keeping it as hot as the steam that entered it--a very important improvement over the old idea; then he worked out a plan by which the steam could be admitted at each end of the cylinder instead of at one end, as was the case with former engines. The latter innovation resulted in the push and pull of the piston rod. So it went."

"How did Watt come to know so much about engines?" asked Stephen.

"Oh, Watt was an engineer by trade--or rather he was a maker of mathematical instruments for the University of Glasgow, where he came into touch with a Newcomen engine. He also made surveys of rivers, harbors, and ca.n.a.ls. So you see it was quite a consistent thing that a man with such a bent of mind should take up the pastime of experimenting with a toy like the steam engine in his leisure hours."

"Did he go so far as to patent it, Henry?" Mrs. Tolman questioned.

"Yes, he did. Many of our scientists either had not the wit to do this, alas, or else they were too impractical to appreciate the value of their ideas. In consequence the glory and financial benefit of what they did was often filched from them. But Watt was a Scotchman and canny enough to realize to some extent what his invention was worth. He therefore obtained a patent on it which was good for twenty-five years; and when, in 1800, this right expired he retired from business with both fame and fortune."

"It is nice to hear of one inventor who got something out of his toil,"

Mrs. Tolman observed.

"Indeed it is. Think of the many men who have slaved day and night, forfeited health, friends, and money to give to the world an idea, and never lived to receive either grat.i.tude or financial reward, dying unknown or entirely forgotten. There is something tragic about the injustice of it. But Watt, I am glad to say, lived long enough to witness the service he had done mankind and enjoy an honored place among the great of the world."

"Is the kind of engine Watt invented now in use?" Doris inquired.

"Yes, that is a double-acting or reciprocating engine of a more perfect type," her father returned. "Mechanics and engineers went on improving Watt's engine just as he had improved those that had preceded it. It is interesting, too, to notice that after thousands of years scientists have again worked around to the steam turbine described so long ago in the Alexandrian records. This engine, although it does away with many of the moving parts introduced by Newcomen, preserves the essential principles of that early engine combined with Watt's later improvements.

To-day we have a number of different kinds of engines, their variety differing with the purpose to which they are applied. Their cost, weight, and the s.p.a.ce they require have been reduced and their power increased, and in addition we have made it possible to run them not only by means of coal or wood but by gasoline, oil, or electricity. We have small, light-weight engines for navigation use; mighty engines to propel our great warships and ocean liners; stationary engines for mills and power plants; to say nothing of the wonderful locomotive engines that can draw the heaviest trains over the highest of mountains. The principle of all these engines is, however, the same and for the brain behind them we must thank James Watt."

"Was it Watt who invented the locomotive, too?" ventured Doris. Her father shook his head.

"The perfecting of the locomotive, my dear, is, as Kipling says, another story."

"Tell it to us."

"Not now, daughter," protested Mr. Tolman. "I am far too hungry; and more than that I am eager to enjoy this beautiful country and forget railroads and locomotives."

"Did you say you were hungry, Henry?" asked Mrs. Tolman.

"I am--starved!" her husband said apologetically. "Isn't it absurd to be hungry so early in the day?"

"It is nearly noon, Dad!" said Steve, glancing down at the clock in the front of the car.

"Noon! Why, I thought it was still the middle of the morning."

"No, indeed! While you have been talking we have come many a mile, and the time has slipped past," his wife said. "If all goes well--" The shot from a bursting tire rent the air.

"Which evidently it does not," interrupted Mr. Tolman grimly, bringing the car to a stop. "How aggravating! We were almost into Palmer, where I had planned for us to lunch. Now it may be some little time before we can get anything to eat."

"Motorist's luck! Motorist's luck, my dear!" cried Mrs. Tolman gaily.

"An automobilist must resign himself to taking cheerfully what comes."

"That is all very well," grumbled her husband, as he clambered out of the car. "Nevertheless you must admit that this mishap on the heels of the other one is annoying."

Stephen also got out and the two bent to examine the punctured tire.

"I should not mind so much if I were not so hungry," murmured Mr.