"What in the world is that?" cried Mr. Job Titus, in alarm.

Tom Swift did not answer. Instead he jumped up from his chair and ran toward the front door. Mr. Titus followed. They both saw a strange sight.

Standing on the front porch, which he seemed to occupy completely, was a large horse, with a saddle twisted underneath him. The animal was looking about him as calmly as though he always made it a practice to come up on the front piazza when stopping at a house.

Off to one side, with a crushed hat on the back of his head, with a coat split up the back, with a broken riding crop in one hand and a handkerchief in the other, sat a dignified, elderly gentleman.

That is, he would have been dignified had it not been for his position and condition. No gentleman can look dignified with a split coat and a crushed hat on, sitting under the nose of a horse on a front piazza, with his raiment otherwise much disheveled, while he wipes his scratched and bleeding face with a handkerchief.

"Bless my--bless my--" began the elderly gentleman, and he seemed at a loss what particular portion of his anatomy or that of the horse, to bless, or what portion of the universe to appeal to, for he ended up with: "Bless everything, Tom Swift!"

"I heartily agree with you, Mr. Damon!" cried Tom. "But what in the world happened?"

"That!" exclaimed Mr. Damon, pointing with his broken crop at the horse on the piazza. "I was riding him when he ran away--just as my motorcycle tried to climb a tree. No more horses for me! I'll stick to airships," and slamming his riding crop down on the porch floor with such force that the horse started back, Mr. Damon arose, painfully enough if the contortions on his face and his grunts of pain went for anything.

"Let me help you!" begged Tom, striding forward. "Mr. Titus, perhaps you will kindly lead the horse down off the piazza?"

"Certainly!" answered the tunnel contractor. "Whoa now!" he called soothingly, as the steed evinced a disposition to sit down on the side railing. "Steady now!"

The horse finally allowed himself to be led down the broad front steps, sadly marking them, as well as the floor of the piazza, with his sharp shoes.

"Ouch! Oh, my back!" exclaimed Mr. Damon, as Tom helped him to stand up.

"Is it hurt?" asked Tom, anxiously.

"No, I've just got what old-fashioned folks call a 'crick' in it," explained the elderly horseman. "But it feels more like a river than a 'crick.' I'll be all right presently."

"How did it happen?" asked Tom, as he led his guest toward the hall. Meanwhile Mr. Titus, wondering what it was all about, had tied the horse to a post out near the street curb, and had re-entered the library.

"I was riding over to see you, Tom, to ask you if you wouldn't go to South America with me," began Mr. Damon, rubbing his leg tenderly.

"South America?" cried Tom, with a sudden look at Mr. Titus.

"Yes, South America. Why, there isn't anything strange in that, is there? You've been to wilder countries, and farther away than that."

"Yes, I know--it's just a coincidence. Go on."

"Let me get where I can sit down," begged Mr. Damon. "I think that crick in my back is running down into my legs, Tom. I feel a bit weak. Let me sit down, and get me a glass of water. I shall be all right presently."

Between them Tom and Mr. Titus assisted the horseman into an easy chair, and there, under the influence of a cup of hot tea, which Mrs. Baggert, the housekeeper, insisted on making for him, he said he felt much better, and would explain the reason for his call which had culminated in such a sensational manner.

And while Mr. Damon is preparing his explanation I will take just a few moments to acquaint my new readers with some facts about Tom Swift, and the previous volumes of this series in which he has played such prominent parts.

Tom Swift was the son of an inventor, and not only inherited his father's talents, but had greatly added to them, so that now Tom had a wonderful reputation.

Mr. Swift was a widower, and he and Tom lived in a big house in Shopton, New York State, with Mrs. Baggert for a housekeeper. About the house, from time to time, shops and laboratories had been erected, until now there was a large and valuable establishment belonging to Tom and his father.

The first volume of this series is entitled, "Tom Swift and His Motor Cycle." It was through a motor cycle that Tom became acquainted with Mr. Wakefield Damon, who lived in a neighboring town. Mr. Damon had bought the motor cycle for himself, but, as he said, one day in riding it the machine tried to climb a tree near the Swift house.

The young inventor (for even then he was working on several patents) ministered to Mr. Damon, who, disgusted with the motor cycle, and wishing to reward Tom, let the young fellow have the machine.

Tom's career began from that hour. For he learned to ride the motor cycle, after making some improvements in it, and from then on the youth had led a busy life. Soon afterward he secured a motor boat and from that it was but a step to an airship.

The medium of the air having been conquered, Tom again turned his attention to the water, or rather, under the water, and he and his father made a submarine. Then he built an electric runabout, the speediest car on the road.

It was when Ton Swift had occasion to send his wireless message from a lonely island where he had been shipwrecked that he was able to do Mr. and Mrs. Nestor a valuable service, and this increased the regard which Miss Mary Nestor felt for the young inventor, a regard that bid fair, some day, to ripen into something stronger.

Tom Swift might have made a fortune when he set out to discover the secret of the diamond makers. But Fate intervened, and soon after that quest he went to the caves of ice, where he and his friends met with disaster. In his sky racer Tom broke all records for speed, and when he went to Africa to rescue a missionary, had it not been for his electric rifle the tide of battle would have gone against him and his party.

Marvelous, indeed, were the adventures underground, which came to Tom when he went to look for the city of gold, but the treasure there was not more valuable than the platinum which Tom sought in dreary Siberia by means of his air glider.

Tom thought his end had come when he fell into captivity among the giants; but even that turned out well, and he brought two of the giants away with him. Koku, one of the two giants, became devotedly attached to the lad, much to the disgust of Eradicate Sampson, the old negro who had worked for the Swifts for a generation, and who, with his mule Boomerang, "eradicated" from the place as much dirt as possible.

With his wizard camera Tom did much to advance the cause of science. His great searchlight was of great help to the United States government in putting a stop to the Canadian smugglers, while his giant cannon was a distinct advance in ordnance, not excepting the great German guns used in the European war.

When Tom perfected his photo telephone the last objection to rendering telephonic conversation admissible evidence in a law court was done away with, for by this invention a person was able to see, as well as to hear, over the telephone wire. One practically stood face to face with the person, miles away, to whom one was talking.

The volume immediately preceding this present one is called: "Tom Swift and His Aerial Warship." The young inventor perfected a marvelous aircraft that was the naval terror of the seas, and many governments, recognizing what an important part aircraft were going to play in all future conflicts, were anxious to secure Tom's machine. But he was true to his own country, though his rivals were nearly successful in their plots against him.

The Mars, which was the name of Tom's latest craft, proved to be a great success, and the United States government purchased it. It was not long after the completion of this transaction that the events narrated in the first chapter of this book took place.

Mr. Damon and Tom had been firm friends ever since the episode of the motor cycle, and the eccentric gentleman (who blessed so many things) often went with Tom on his trips. Besides Mary Nestor, Tom had other friends. The one, after Miss Nestor, for whom he cared most (if we except Mr. Damon) was Ned Newton, who was employed in a Shopton bank. Ned also had often gone with Tom, though lately, having a better position, he had less time to spare.

"Well, do you feel better, Mr. Damon?" asked Tom, after a bit.

"Yes, very much, thank you. Bless my pen wiper! but I thought I was done for when I saw my horse bolt for your front stoop. He rushed up it, fell down, but, fortunately, I managed to get out of his way, though the saddle girth slipped. And all I could think of was that my wife would say: 'I told you so!' for she warned me not to ride this animal.

"But he never ran away with me before, and I was in a hurry to get over to see you, Tom. Now then, let's get down to business. Will you go to South America with me?"

"Whereabout in South America are you going, Mr. Damon, and why?" Tom asked.

"To Peru, Tom."

"What a coincidence!" exclaimed Mr. Titus.

"I beg your pardon?" said Mr. Damon, interrogatively.

"I said what a coincidence. I am going there myself."

"Excuse me," interposed Tom, "I don't believe, in the excitement of the moment, I introduced you gentlemen. Allow me--Mr. Damon--Mr. Titus."

The presentation over, Mr. Damon went on:

"You see, Tom, I have lately invested considerable money in a wholesale drug concern. We deal largely in Peruvian remedies, principally the bark of the cinchona tree, from which quinine is made. Of late there has been some trouble over our concession from the Peruvian government, and the company has decided to send me down there to investigate.

"Of course, as soon as I made up my mind to go I thought of you. So I came over to see if you would not accompany me. All went well until I reached your front gate. Then my horse became frightened by a yellow toy balloon some boy was blowing up in the street and bolted with me. I suppose if it had been a red or green balloon the effect would have been the same. However, here I am, somewhat the worse for wear. Now Tom, what do you say? Will you go to South America--to Peru--with me, and help look up this Quinine business?"

Once more Mr. Titus and Tom looked at each other.