CHAPTER VIII.
A DRAWING LESSON.
For a moment Monsieur Dalize was disconcerted, and knew not what to sayin answer. Happily, Monsieur Roger came to his aid. He took the bookfrom Miette's hands, looked at the engraving, and said, quietly,--
"Why, certainly, my dear young friend, the gentleman who made thatdrawing ought to know something about chemistry and physical science."
"How so?" said Miette, astonished.
"Why, if he did not know the laws of physical science and of chemistry,he has, none the less, and perhaps even without knowing it himself,availed himself of the results of chemistry and physical science."
Miette took the book back again, looked at the drawing with care, andsaid,--
"Still, there are not in this drawing instruments or apparatus, ormachines such as I have seen in my brother's books."
"But," answered Monsieur Roger, smiling, "it is not necessary that youshould see instruments and apparatus and machines, as you say, to be inthe presence of physical phenomena; and I assure you, my dear child,that this drawing which is under our eyes is connected with chemistryand physical science."
Miette now looked up at Monsieur Roger to see if he was not making funof her. Monsieur Roger translated this dumb interrogation, and said,--
"Come, now! what does this drawing represent? Tell me yourself."
"Why, it represents two peasants,--a man and a woman,--who have returnedhome wet in the storm, and who are warming and drying themselves beforethe fire."
"It is, in fact, exactly that."
"Very well, sir?" asked Miette.
And in this concise answer she meant to say, "In all that, what do yousee that is connected with chemistry or physical science?"
"Very well," continued Monsieur Roger; "do you see this light mist, thisvapor, which is rising from the cloak that the peasant is drying beforethe fire?"
"Yes."
"Well, that is physical science," said Monsieur Roger.
"How do you mean?" asked Miette.
"I will explain in a moment. Let us continue to examine the picture. Doyou see that a portion of the wood is reduced to ashes?"
"Yes."
"Do you also remark the flame and the smoke which are rising up thechimney?"
"Yes."
"That is chemistry."
"Ah!" said Miss Miette, at a loss for words.
Every one was listening to Monsieur Roger, some of them interested, theothers amused. Miette glanced over at her friend Paul.
"What do you think of that?" she asked.
Paul did not care to reply. Albert wished to speak, but he stopped at agesture from his father. Monsieur Dalize knew that the real interest ofthis scene lay with Monsieur Roger, the scientist, who was already lovedby all this little world. Miette, as nobody else answered, returned toMonsieur Roger.
"But why," she asked, "is that physical science? Why is it chemistry?"
"Because it is physical science and chemistry," said Monsieur Roger,simply.
"Oh, but you have other reasons to give us!" said Madame Dalize, whounderstood what Monsieur Roger was thinking of.
"Yes," added Miette.
And even Paul, with unusual curiosity, nodded his head affirmatively.
"The reasons will be very long to explain, and would bore you," saidMonsieur Dalize, certain that he would in this way provoke a protest.
The protest, in fact, came.
Monsieur Roger was obliged to speak.
"Well," said he, still addressing himself to Miss Miette, "this drawingis concerned with physical science, because the peasant, in placing hiscloak before the heat of the fire, causes the phenomenon of evaporationto take place. The vapor which escapes from the damp cloth is water, isnothing but water, and will always be water under a different form. Itis water modified, and modified for a moment, because this vapor, comingagainst the cold wall or other cold objects, will condense. That is tosay, it will become again liquid water,--water similar to that which itwas a moment ago; and that is a physical phenomenon,--for physicalscience aims to study the modifications which alter the form, the color,the appearance of bodies, but only their temporary modifications, whichleave intact all the properties of bodies. Our drawing is concerned withchemistry, because the piece of wood which burns disappears, leaving inits place cinders in the hearth and gases which escape through thechimney. Here there is a complete modification, an absolute change ofthe piece of wood. Do what you will, you would be unable, by collectingtogether the cinders and gases, to put together again the log of woodwhich has been burned; and that is a chemical phenomenon,--for the aimof chemistry is to study the durable and permanent modifications, afterwhich bodies retain none of their original properties. Another examplemay make more easy this distinction between physical science andchemistry. Suppose that you put into the fire a bar of iron. That barwill expand and become red. Its color, its form, its dimensions will bemodified, but it will always remain a bar of iron. That is a physicalphenomenon. Instead of this bar of iron, put in the fire a bit ofsulphur. It will flame up and burn in disengaging a gas of a peculiarodor, which is called sulphuric acid. This sulphuric-acid gas can becondensed and become a liquid, but it no longer contains the propertiesof sulphur. It is no longer a piece of sulphur, and can never againbecome a piece of sulphur. The modification of this body is thereforedurable, and therefore permanent. Now, that is a chemical phenomenon."
Monsieur Roger stopped for a moment; then, paying no apparent attentionto Paul, who, however, was listening far more attentively than one couldimagine he would, he looked at Miette, and said,--
"I don't know, my child, if I have explained myself clearly enough; butyou must certainly understand that in their case the artist hasrepresented, whether he wished to or not, the physical phenomenon andthe chemical phenomenon."
"Yes, sir," answered Miette, "I have understood quite well."
"Well," said Monsieur Dalize, "since you are so good a teacher, don'tyou think that you could, during vacation, cause a little chemistry anda little physical science to enter into that little head?" And hepointed to Paul Solange.
The latter, notwithstanding the sentiment of respectful sympathy whichhe felt for Monsieur Roger, and although he had listened with interestto his explanations, could not prevent a gesture of fear, so pronouncedthat everybody began to laugh.
Miette, who wished to console her good friend Paul and obtain his pardonfor her teasing, came up to him, and said,--
"Come, console yourself, Paul; I will let you take my portrait a dozentimes, as you did last year,--although it is very tiresome to pose for aportrait."
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