xxxviii CONTENTS. 



BOOK m. 



METHODS OF MEASUREMENT. 

 CHAPTER XIII. 



THE EXACT MEASUllEMENT OF PHENOMENA. 

 SECTION PAGE 



1. The Exact Measurement of Phenomena '270 



2. Division of the Subject 274 



3. Continuous quantity 274 



4. The Fallacious Indications of the Senses 276 



5. Complexity of Quantitative Questions 278 



6. The IViethods of Accurate Measurement 282 



7. Conditions of Accurate Measurement 282 



8. Measuring Instruments 284 



9. The Method of Kcpetition 288 



10. Measurements by Natural Coincidence 292 



11. Modes of Indirect Measurement 296 



12. Comparative Use of Measuring Instruments 299 



13. Systematic Performance of Measurements 300 



14. The Pendulum 302 



15. Attainable Accuracy of Measurement 303 



CHAPTER XIV. 



UNITS AND STANDARDS OF MEASUREMENT. 



1. Units and Standards of Measurement 30.'> 



2. Standard Unit of Time 307 



3. The Unit of Sjiace and the Bar Standard 312 



4. The Terrestrial Standard 314 



5. The Pendulum Standard 315 



6. Unit of Density 316 



7. Unit of Mass 317 



8. Natural System of Standards 319 



9. Subsidiary Units 320 



10. Derived Units 321 



11. I^rovisional Units 323 



12,, Theoiy of Dimensions 325 



13. Natural Constants 328 



14. Mathematical Constants 330 



15. Physical Constants 331 



16. Astronomical Constants , 332 



17. Terrestrial Numbers 333 



18. Organic Numbiirs 333 



19 Social Numbers 334 



