NATURAL PHILOSOPHY. 



[Lesson IV. 



have no extension, it cannot enter into the 

 composition of a body occupying space. 



31. T. What do you gather from all 

 the facts and observations you have stated ? 



P. That all bodies are composed of 

 minute particles, which cannot be further 

 disintegrated, but are undivisible. 



/'. What name have these particles 

 received from natural philosophers ? 



P. Atoms. If, however, we speak of 

 the particles of a mass, without wishing 

 actually to describe them as the ultimate 

 portions, we employ the term molecules. 



33. T. Then it appears that a molecule 

 is not the same as an atom ; will you ex- 

 plain the difference ? 



P. A molecule is supposed to be 

 formed of several atoms, arranged according 

 to some determinate figure, and generally 

 signifies the component parts of a body too 

 small for sensual perception. 



:;i. 7'. -Has the knowledge of the con- 

 stitution of bodies thus formed been ap- 

 plied? 



P. Yes. Natural philosophers and 

 chemists have universally embraced the 

 hich has received the name of the 

 atomic theory, or theory of atoms. 



GKXF.RAL QUESTIONS ON LESSON III. 



1. Are all bodies divisible ? 



2. Give some examples of the divisibility 

 of matter from the organized world. 



3. C;ui you give a familiar example of 

 the divisibility of matter ? 



4. Can we always prove the divisibility 

 of matter by our senses ? 



5. Is there any limit to the divisibility 

 of matter ? 



0'. What is the difference between an 

 atom, a molecule, and a particle? 



7. "What name has the fundamental view 

 of the constitution of bodies received ? 



LESSON IV. 



RECAPITULATION, &c. THE study of the laws of Natural Philosophy enabled 

 Hallam to discover that matter was capable of division, and he applied his knowh <!:,(> 

 to many useful purposes. The mountain on the borders of the marsh where he had 

 taken up his abode, was barren, and he therefore rented a portion of it for a small sum : 

 on this he built a hut, and formed lime. The lime he sold to the fanners ; and by fru- 

 gality and industry, was enabled to purchase a plot of ground on which to build his 

 house. The house he now built was formed of stone, procured from the mountain's 

 side, united with mortar made from lime he manufactured himself. To procure this 

 stone, he was obliged to have recourse to Natural Philosophy as his assistant, and by 

 means of judiciously conducted experiments and observations, he was enabled to accom- 

 plish ten times the amount of work he otherwise could have done, if unacquainted 

 with Natural Philosophy. 



QUESTIONS. 



.',3. T. I remember that you said one 

 of the essential properties of a body was 

 - n. 11. IT Y. Pray what do you mean 

 by the term ? 



P. Every body must occupy a certain 

 amount of space, which space will, of course, 

 be in proportion to its magnitude. Exten- 

 sibility is the property observed in bodies 

 to have their volume enlarged without in- 

 creasing their mass. 



36. T. What do you mean by the 

 volume of a body? 



P. It is the bulk or size of a body, 

 being the quantity of space included within 

 its external surfaces. 



37. T. How do you estimate the bulk 

 or volume of bodies? 



P. By the quantity of their dimensions ; 

 or in other words, by their length, breadth, 

 and depth. 



38. T. You have just said that a body 

 may have its volume enlarged without in- 



Qg its mass; how is this possible? 



