230 fRA OMENTS F SCIENCE. 
significance imparted to them. The swing, the see-saw; 
the tension of the giant-stride ropes, the fall and rebound 
of the football, the advantage of a small boy over a large 
one when turning short, particularly in slippy weather; all 
became subjects of investigation. A lady stands before a 
looking-glass, of her own height; it was required to know 
how much of the glass was really useful to her? We 
learned with pleasure the economic fact that she might 
dispense with the lower half and see her whole figure not- 
withstanding. It was also pleasant to prove bv mathe- 
matics, 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 deter- 
mine 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 down- 
ward. All these things were sources of wonder and de- 
light 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 
philosophers 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 importance, 
I believe it to be that of the schoolmaster; and if there be 
a position where selfishness and incompetence do most seri- 
ous mischief, by lowering the moral tone and exciting 
irreverence and cunning where reverence and noble truth- 
fulness ought to be the feelings evoked, it is that of the 
principal of a school. When a man of enlarged heart and 
mind comes among boys when he allows his spirit to 
