318 FRAGMENTS OF SCIENCE 



to prove by mathematics, and verify by experiment, that 

 the angular velocity of a reflected beam is twice that of 

 the mirror which reflects it. From the hum of a bee we 

 were able to determine the number of times the insect 

 flaps its ^ wings in a second. Following up our researches 

 upon the pendulum, we learned how Colonel Sabine had 

 made it the means of determining the figure of the earth; 

 and we were also startled by the inference which the 

 pendulum enabled us to draw, that if the diurnal velocity 

 of the earth were seventeen times its present amount, the 

 centrifugal force at the equator would be precisely equal 

 to the force of gravitation, so that an inhabitant of those 

 regions would then have the same tendency to fall upward 

 as downward. All these things were sources of wonder 

 and delight to us: and when we remembered that we 

 were gifted with the powers which had reached such 

 results, and that the same great field was ours to work 

 in, our hopes arose that at some future day we might 

 possibly push the subject a little further, and add our 

 own victories to the conquests already won. 



I ought to apologize to you for dwelling so long upon 

 this subject; but the days spent among these young phi- 

 losophers made a deep impression on me. I learned 

 among them something of myself and of human nature, 

 and obtained some notion of a teacher's vocation. If 

 there be one profession in England of paramount impor- 

 tance, I believe it to be that of the schoolmaster; and 

 if there be a position where selfishness and incompetence 

 do most serious mischief, by lowering the moral tone and 

 exciting irreverence and cunning where reverence and 

 noble truthfulness ought to be the feelings evoked, it 

 is that of the principal of a school. When a man of 



