CHAPTER XIX.

EXPERIMENT.

1. Experiment 416

2. Exclusion of Indifferent Circumstances 419

3. Simplification of Experiments 422

4. Failure in the Simplification of Experiments 424

5. Removal of Usual Conditions 426

6. Interference of Unsuspected Conditions 428

7. Blind or Test Experiments 433

8. Negative Results of Experiment 434

9. Limits of Experiment 437