CHAPTER IX.
THE TOWER OF HEURTEBIZE
Next morning at six o'clock Paul Solange opened the door of the château and stepped out on to the lawn. He held a sketch-book in his hand. He directed his steps along a narrow pathway, shaded by young elms, towards one of the gates of the park. At a turning in the alley he found himself face to face with Monsieur Roger, who was walking slowly and thoughtfully. Paul stopped, and in his surprise could not help saying,—
"Monsieur Roger, already up?"
Monsieur answered, smiling,—
"But you also, Master Paul, you are, like me, already up. Are you displeased to meet me?"
"Oh, no, sir," Paul hastened to say, blushing a little. "Why should I be displeased at meeting you?"
"Then, may I ask you where you are going so early in the morning?"
"Over there," said Paul, stretching his hand towards a high wooded hill: "over there to Heurtebize."
"And what are you going to do over there?"
Paul answered by showing his sketch-book.
"Ah, you are going to draw?"
"Yes, sir; I am going to draw, to take a sketch of the tower; that old tower which you see on the right side of the hill."
"Well, Master Paul, will you be so kind," asked Monsieur Roger, "as to allow me to go with you and explore this old tower?"
Paul, on hearing this proposal, which he could not refuse, made an involuntary movement of dismay, exactly similar to that he had made the night before.
"Oh, fear nothing," said Monsieur Roger, good-naturedly. "I will not bore you either with physical science nor chemistry. I hope you will accept me, therefore, as your companion on the way, without any apprehensions of that kind of annoyance."
"Then, let us go, sir," answered Paul, a little ashamed to have had his thoughts so easily guessed.
They took a short cut across the fields, passing wide expanses of blossoming clover; they crossed a road, they skirted fields of wheat and of potatoes. At last they arrived upon the wooded hill of Heurtebize, at the foot of the old tower, which still proudly raised its head above the valleys.
"What a lovely landscape!" said Monsieur Roger, when he had got his breath.
"The view is beautiful," said Paul, softly; "but it is nothing like the view you get up above there."
"Up above?" said Monsieur Roger, without understanding.
"Yes, from the summit of the tower."
"You have climbed up the tower?"
"Several times."
"But it is falling into ruins, this poor tower; it has only one fault, that of having existed for two or three hundred years."
"It is indeed very old," answered Paul; "it is the last vestige of the old château of Sainte-Gemme, which, it is said, was built in the sixteenth century, or possibly even a century or two earlier; nobody is quite certain as to the date; at all events, the former proprietors several years ago determined to preserve it, and they even commenced some repairs upon it. The interior stairway has been put in part into sufficiently good condition to enable you to use it, if you at the same time call a little bit of gymnastics to your aid, as you will have to do at a few places. And I have used it in this way very often; but please now be good enough to–"
Paul stopped, hesitating.
"Good enough to what? Tell me."
Then Paul Solange added,—
"To say nothing of this to Madame Dalize. That would make her uneasy."
"Not only will I say nothing, my dear young friend, but I will join you in the ascent,—for I have the greatest desire to do what you are going to do, and to ascend the tower with you."
Paul looked at Monsieur Roger, and said, quickly,—
"But, sir, there is danger."
"Bah! as there is none for you, why should there be danger for me?"
Somewhat embarrassed, Paul replied,—
"I am young, sir; more active than you, perhaps, and–"
"If that is your only reason, my friend, do not disturb yourself. Let us try the ascent."
"On one condition, sir."
"What is that?"
"That I go up first."
"Yes, my dear friend, I consent. You shall go first," said Monsieur Roger, who would have himself suggested this if the idea had not come to Paul.
Both of them, Monsieur Roger and Paul, had at this moment the same idea of self-sacrifice. Paul said to himself, "If any accident happens, it will happen to me, and not to Monsieur Roger." And Monsieur Roger, sure of his own strength, thought, "If Paul should happen to fall, very likely I may be able to catch him and save him."
Luckily, the ascent, though somewhat difficult, was accomplished victoriously, and Monsieur Roger was enabled to recognize that the modified admiration which Paul Solange felt for the landscape, as seen from below, was entirely justified.
Paul asked,—
"How high is this tower? A hundred feet?"
"Less than that, I think," answered Monsieur Roger. "Still, it will be easy to find out exactly in a moment."
"In a moment?" asked Paul.
"Yes, in a moment."
"Without descending?"
"No; we will remain where we are."
Paul made a gesture which clearly indicated, "I would like to see that."
Monsieur Roger understood.
"There is no lack of pieces of stone in this tower; take one," said he to Paul.
Paul obeyed.
"You will let this stone fall to the earth at the very moment that I tell you to do so."
Monsieur Roger drew out his watch and looked carefully at the second-hand.
"Now, let go," he said.
Paul opened his hand; the stone fell. It could be heard striking the soil at the foot of the tower. Monsieur Roger, who during the fall of the stone had had his eyes fixed upon his watch, said,—
"The tower is not very high." Then he added, after a moment of reflection, "The tower is sixty-two and a half feet in height."
Paul looked at Monsieur Roger, thinking that he was laughing at him. Monsieur Roger lifted his eyes to Paul; he looked quite serious. Then Paul said, softly,—
"The tower is sixty feet high?"
"Sixty-two and a half feet,—for the odd two and a half feet must not be forgotten in our computation."
Paul was silent. Then, seeing that Monsieur Roger was ready to smile, and mistaking the cause of this smile, he said,—
"You are joking, are you not? You cannot know that the tower is really sixty feet high?"
"Sixty-two feet and six inches," repeated Monsieur Roger again. "That is exact. Do you want to have it proved to you?"
"Oh, yes, sir," said Paul Solange, with real curiosity.
"Very well. Go back to the château, and bring me a ball of twine and a yard-measure."
"I run," said Paul.
"Take care!" cried Monsieur Roger, seeing how quickly Paul was hurrying down the tower.
When Paul had safely reached the ground, Monsieur Roger said to himself, with an air of satisfaction,—
"Come, come! we will make something out of that boy yet!"
CHAPTER X.
PHYSICAL SCIENCE
Paul returned to the tower more quickly than Monsieur Roger had expected. Instead of returning to the château, he had taken the shortest cut, had reached the village, and had procured there the two things wanted. He climbed up the tower and arrived beside Monsieur Roger, holding out the ball of twine and the yard-stick.
"You are going to see, you little doubter, that I was not wrong," said Monsieur Roger.
He tied a stone to the twine, and let it down outside the tower to the ground.
"This length of twine," he said, "represents exactly the height of the tower, does it not?"
"Yes, sir," answered Paul.
Monsieur Roger made a knot in the twine at the place where it rested on the top of the tower. Then he asked Paul to take the yard-stick which he had brought, and to hold it extended between his two hands. Then, drawing up the twine which hung outside the tower, he measured it yard by yard. Paul counted. When he had reached the number sixty, he could not help bending over to see how much remained of the twine.
"Ah, sir," he cried, "I think you have won."
"Let us finish our count," said Monsieur Roger, quietly.
And Paul counted,—
"Sixty-one, sixty-two,—sixty-two feet–"
"And?"
"And six inches!" cried Paul.
"I have won, as you said, my young friend," cried Monsieur Roger, who enjoyed Paul's surprise. "Now let us cautiously descend and return to the château, where the breakfast-bell will soon ring."
The descent was made in safety, and they directed their steps towards Sainte-Gemme. Paul walked beside Monsieur Roger without saying anything. He was deep in thought.
Monsieur Roger, understanding what was going on in the brain of his friend, took care not to disturb him. He waited, hoping for an answer. His hope was soon realized. As they reached the park, Paul, who, after thinking a great deal, had failed to solve the difficulty, said, all of a sudden,—
"Monsieur Roger!"
"What, my friend?"
"How did you measure the tower?"
Monsieur Roger looked at Paul, and, affecting a serious air, he said,—
"It is impossible, entirely impossible for me to answer."
"Impossible?" cried Paul, in surprise.
"Yes, impossible."
"Why, please?"
"Because in answering I will break the promise that I have made you,—the promise to say nothing about chemistry or physical science."
"Ah!" said Paul, becoming silent again.
Monsieur Roger glanced at his companion from the corner of his eye, knowing that his curiosity would soon awake again. At the end of the narrow, shady pathway they soon saw the red bricks of the château shining in the sun; but Paul had not yet renewed his question, and Monsieur Roger began to be a little uneasy,—for, if Paul held his tongue, it would show that his curiosity had vanished, and another occasion to revive it would be difficult to find.
Luckily, Paul decided to speak at the very moment when they reached the château.
"Then," said he, expressing the idea which was uppermost,—"Then it is physical science?"
Monsieur Roger asked, in an indifferent tone,—
"What is physical science?"
"Your method of measuring the tower."
"Yes, it is physical science, as you say. Consequently, you see very well that I cannot answer you."
"Ah, Monsieur Roger," said Paul, embarrassed, "you are laughing at me."
"Not at all, my friend. I made a promise; I must hold to it. I have a great deal of liking for you, and I don't want you to dislike me."
"Oh, sir!"
Suddenly they heard the voice of Monsieur Dalize, who cried, cheerfully,—
"See, they are already quarrelling!"
For some moments Monsieur Dalize, at the door of the vestibule, surrounded by his wife and his children, had been gazing at the two companions. Monsieur Roger and Paul approached.
"What is the matter?" asked Monsieur Dalize, shaking hands with his friend.
"A very strange thing has happened," answered Monsieur Roger.
"And what is that?"
"Simply that Master Paul wants me to speak to him of physical science."
An astonished silence, soon followed by a general laugh, greeted these words. Miss Miette took a step forward, looked at Paul with an uneasy air, and said,—
"Are you sick, my little Paul?"
Paul, confused, kept silent, but he answered by a reproachful look the ironical question of his friend Miette.
"But whence could such a change have come?" asked Madame Dalize, addressing Monsieur Roger. "Explain to us what has happened."
"Here are the facts," answered Monsieur Roger. "We had climbed up the tower of Heurtebize–"
Madame Dalize started, and turned a look of uneasiness towards Paul.
"Paul was not at fault," Monsieur Roger hastened to add. "I was the guilty one. Well, we were up there, when Master Paul got the idea of estimating the height of the tower. I answered that nothing was more simple than to know it at once. I asked him to let fall a stone. I looked at my watch while the stone was falling, and I said, 'The tower is sixty-two feet and six inches high.' Master Paul seemed to be astonished. He went after a yard-stick and some twine. We measured the tower, and Master Paul has recognized that the tower is in fact sixty-two feet and six inches high. Now he wants me to tell him how I have been able so simply, with so little trouble, to learn the height. That is a portion of physical science; and, as I made Master Paul a promise this very morning not to speak to him of physical science nor of chemistry, you see it is impossible for me to answer."
Monsieur Dalize understood at once what his friend Roger had in view, and, assuming the same air, he answered,—
"Certainly, it is impossible; you are perfectly right. You promised; you must keep your promise."
"Unless," said Miss Miette, taking sides with her friend Paul,—"unless Paul releases Monsieur Roger from his promise."
"You are entirely right, my child," said Monsieur Roger; "should Paul release me sufficiently to ask me to answer him. But, as I remarked to you a moment ago, I fear that he will repent too quickly, and take a dislike to me. That I should be very sorry for."
"No, sir, I will not repent. I promise you that."
"Very well," said Miette; "there is another promise. You know that you will have to keep it."
"But," answered Monsieur Roger, turning to Paul, "it will be necessary for me to speak to you of weight, of the fall of bodies, of gravitation; and I am very much afraid that that will weary you."
"No, sir," answered Paul, very seriously, "that will not weary me. On the contrary, that will interest me, if it teaches me how you managed to calculate the height of the tower."
"It will certainly teach you that."
"Then I am content," said Paul.
"And I also," said Monsieur Roger to himself, happy to have attained his object so soon.
CHAPTER XI.
THE SMOKE WHICH FALLS
In the evening, after dinner, Monsieur Roger, to whom Paul recalled his promise, asked Miette to go and find him a pebble in the pathway before the château. When he had the bit of stone in his hand, Monsieur Roger let it fall from the height of about three feet.
"As you have just heard and seen," said he, addressing Paul, "this stone in falling from a small height produces only a feeble shock, but if it falls from the height of the house upon the flagstones of the pavement, the shock would be violent enough to break it."
Monsieur Roger interrupted himself, and put this question to Paul:
"Possibly you may have asked yourself why this stone should fall. Why do bodies fall?"
"Goodness knows," said the small voice of Miss Miette in the midst of the silence that followed.
"Miette," said Madame Dalize, "be serious, and don't answer for others."
"But, mamma, I am sure that Paul would have answered the same as I did:—would you not, Paul?"
Paul bent his head slightly as a sign that Miette was not mistaken.
"Well," continued Monsieur Roger, "another one before you did ask himself this question. It was a young man of twenty-three years, named Newton. He found himself one fine evening in a garden, sitting under an apple-tree, when an apple fell at his feet. This common fact, whose cause had never awakened the attention of anybody, filled all his thoughts; and, as the moon was shining in the heavens, Newton asked himself why the moon did not fall like the apple."
"That is true," said Miette; "why does not the moon fall?"
"Listen, and you will hear," said Monsieur Dalize.
Monsieur Roger continued:
"By much reflection, by hard work and calculation, Newton made an admirable discovery,—that of universal attraction. Yes, he discovered that all bodies, different though they may be, attract each other: they draw towards each other; the bodies which occupy the celestial spaces,—planets and suns,—as well as the bodies which are found upon our earth. The force which attracts bodies towards the earth, which made this stone fall, as Newton's apple fell, has received the name of weight. Weight, therefore, is the attraction of the earth for articles which are on its surface. Why does this table, around which we find ourselves, remain in the same place? Why does it not slide or fly away? Simply because it is retained by the attraction of the earth. I have told you that all bodies attract each other. It is therefore quite true that in the same way as the earth attracts the table, so does the table attract the earth."
"Like a loadstone," said Albert Dalize.
"Well, you may compare the earth in this instance to a loadstone. The loadstone draws the iron, and iron draws the loadstone, exactly as the earth and the table draw each other; but you can understand that the earth attracts the table with far more force than the table attracts the earth."
"Yes," said Miette; "because the earth is bigger than the table."
"Exactly so. It has been discovered that bodies attract each other in proportion to their size,—that is to say, the quantity of matter that they contain. On the other hand, the farther bodies are from each other the less they attract each other. I should translate in this fashion the scientific formula which tells us that bodies attract each other in an inverse ratio to the square of the distance. I would remind you that the square of a number is the product obtained by multiplying that number by itself. So all bodies are subject to that force which we call weight; all substances, all matter abandoned to itself, falls to the earth."
Just here Miss Miette shifted uneasily on her chair, wishing to make an observation, but not daring.
"Come, Miss Miette," said Monsieur Roger, who saw this manoeuvre, "you have something to tell us. Your little tongue is itching to say something. Well, speak; we should all like to hear you."
"Monsieur Roger," said Miette, "is not smoke a substance?"
"Certainly; the word substance signifies something that exists. Smoke exists. Therefore it is a substance."
"Then," replied Miette, with an air of contentment with herself, "as smoke is a substance, there is one substance which does not fall to the earth. Indeed, it does just the opposite."
"Ah! Miss Miette wants to catch me," said Monsieur Roger.
Miette made a gesture of modest denial, but at heart she was very proud of the effect which she had produced, for every one looked at her with interest.
"To the smoke of which you speak," continued Monsieur Roger, "you might add balloons, and even clouds."
"Certainly, that is true," answered Miette, näively.
"Very well; although smoke and balloons rise in the air instead of falling, although clouds remain suspended above our heads, smoke and balloons and clouds are none the less bodies with weight. What prevents their fall is the fact that they find themselves in the midst of the air, which is heavier than they are. Take away the air and they would fall."
"Take away the air?" cried Miette, with an air of doubt, thinking that she was facing an impossibility.
"Yes, take away the air," continued Monsieur Roger; "for that can be done. There even exists for this purpose a machine, which is called an air-pump. You place under a glass globe a lighted candle. Then you make a vacuum,—that is to say, by the aid of the air-pump you exhaust the air in the globe; soon the candle is extinguished for want of air, but the wick of the candle continues for some instants to produce smoke. Now, you think, I suppose, that that smoke rises in the globe?"
"Certainly," said Miette.
"No, no, not at all; it falls."
"Ah! I should like to see that!" cried Miette.
"And, in order to give you the pleasure of seeing this, I suppose you would like an air-pump?"
"Well, papa will buy me one.—Say, papa, won't you do it, so we may see the smoke fall?"
"No, indeed!" said Monsieur Dalize; "how can we introduce here instruments of physical science during vacation? What would Paul say?"
"Paul would say nothing. I am sure that he is just as anxious as I am to see smoke fall.—Are you not, Paul?"
And Paul Solange, already half-conquered, made a sign from the corner of his eye to his little friend that her demand was not at all entirely disagreeable to him.
CHAPTER XII.
AT THE CENTRE OF THE EARTH
Monsieur Roger, hiding his satisfaction, seemed to attach no importance to this request of Miette under the assent given by Paul. Wishing to profit by the awakened curiosity of his little friend, he hastened to continue, and said,—
"Who wants to bring me a bit of cork and a glass of water?"
"I! I!" cried Miette, running.
When Miette had returned with the articles, Monsieur Roger continued:
"I told you a moment ago that if balloons and smoke and clouds do not fall, it is because they find themselves in the midst of air which is heavier than they are. I am going to try an experiment which will make you understand what I have said."
Monsieur Roger took the cork, raised his hand above his head, and opened his fingers: the cork fell.
"Is it a heavy body?" said he. "Did it fall to the ground?"
"Yes," cried Paul and Miette together.
Then Monsieur Roger placed the glass of water in front of him, took the cork, which Miette had picked up, and forced it with his finger to the bottom of the glass; then he withdrew his finger, and the cork mounted up to the surface again.
"Did you see?" asked Monsieur Roger.
"Yes," said Miss Miette.
"You remarked something?"
"Certainly: the cork would not fall, and you were obliged to force it into the water with your finger."
"And not only," continued Monsieur Roger, "it would not fall, as you say, but it even hastened to rise again as soon as it was freed from the pressure of my finger. We were wrong, then, when we said that this same cork is a heavy body?"
"Ah, I don't know," said Miette, a little confused.
"Still, we must know. Did this cork fall just now upon the ground?"
"Yes."
"Then it was a heavy body?"
"Yes."
"And now that it remains on the surface of the water, that it no longer precipitates itself towards the earth, it is no longer a heavy body?"
This time Miette knew not what to answer.
"Well, be very sure," continued Monsieur Roger, "that it is heavy. If it does not fall to the bottom of the water, it is because the water is heavier than it. The water is an obstacle to it. Nevertheless, it is attracted, like all bodies, towards the earth, or, more precisely, towards the centre of the earth."
"Towards the centre of the earth?" repeated Miette.
"Yes, towards the centre of the earth. Can Miss Miette procure for me two pieces of string and two heavy bodies,—for example, small pieces of lead?"
"String, yes; but where can I get lead?" asked Miette.
"Look in the box where I keep my fishing-tackle," said Monsieur Dalize to his daughter, "and find two sinkers there."
Miette disappeared, and came back in a moment with the articles desired. Monsieur Roger tied the little pieces of lead to the two separate strings. Then he told Miette to hold the end of one of these strings in her fingers. He himself did the same with the other string. The two strings from which the sinkers were suspended swayed to and fro for some seconds, and then stopped in a fixed position.
"Is it not evident," said Monsieur Roger, "that the direction of our strings is the same as the direction in which the force which we call weight attracts the bodies of lead? In fact, if you cut the string, the lead would go in that direction. The string which Miss Miette is holding and that which I hold myself seem to us to be parallel,—that is to say, that it seems impossible they should ever meet, however long the distance which they travel. Well, that is an error. For these two strings, if left to themselves, would meet exactly at the centre of the earth."
"Then," said Miette, "if we detach the sinkers, they would fall, and would join each other exactly at the centre of the earth?"
"Yes, if they encountered no obstacle; but they would be stopped by the resistance of the ground. They would attempt to force themselves through, and would not succeed."
"Why?"
"Why, if the ground which supports us did not resist, we would not be at this moment chatting quietly here on the surface of the earth; drawn by gravity, we would all be–"
"At the centre of the earth!" cried Miette.
"Exactly. And it might very well happen that I would not then be in a mood to explain to you the attraction of gravity."
"Yes, that is very probable," said Miss Miette, philosophically. Then she added, "If, instead of letting these bits of lead fall upon the ground, we let them fall in water?"
"Well, they would approach the centre of the earth for the entire depth of the water."
Miette had mechanically placed the sinker above the glass of water. She let it fall into it; the cork still swam above.
"Why does the lead fall to the bottom of the water, and why does the cork not fall?"
"Why," said Albert, "because lead is heavier than cork."
Miette looked at her brother, and then turned her eyes towards Monsieur Roger, as if the explanation given by Albert explained nothing, and finally she said,—
"Of course lead is heavier than cork; but why is it heavier?"
"My child, you want to know a great deal," said Madame Dalize.
"Ah, mamma, it is not my fault,—it is Paul's, who wants to know, and does not like to ask. I am obliged to ask questions in his stead."
That was true. Paul asked no questions, but he listened with attention, and his eyes seemed to approve the questions asked by his friend Miette. Monsieur Roger had observed with pleasure the conduct of his young friend, and it was for him, while he was looking at Miette, the latter continued:
"Tell us, Monsieur Roger, why is lead heavier than cork?"
"Because its density is greater," answered Monsieur Roger, seriously.
"Ah!" murmured Miette, disappointed; and, as Monsieur Roger kept silent, she added, "What is density?"
"It would take a long time to explain."
"Tell me all the same."
Monsieur Roger saw at this moment that Paul was beckoning to Miette to insist.
"Goodness!" said he, smiling at Paul; "Miss Miette was right just now. It is you that wish me to continue the questions!"