34 KANSAS ACADEMY OF SCIENCE. 
i CHEMISTRY A AND PHYSICS. 
RELATIVITY IN SCIENCE. 
BY E. B. KNERR, ATCHISON. 
Read before the Academy October 28, 1897. 
All human knowledge is relative. It is beyond the power of man to conceive 
an isolated fact. We know only by comparison. There is nothing new in this; 
the most ancient philosophers recognized the force of this truth. Evidently, 
then, to fully comprehend a fact, we must know it in all its bearings. But again, 
that is quite impossible, for to know all of any one thing is to comprise a knowl- 
edge of the whole universe, so intimately bound up is each fact in every other. 
As Tennyson has beautifully put it: 
‘*Flower in the crannied wall, 
I pluck you out of the crannies, 
Hold you there, root and all, in my hand, 
Little flower: but if I could understand 
What you are, root and all, and all in all, 
I should know what God and man is.’’ 
Only because of this comparative nature of all knowledge is it possible to 
have a science; but students of science are frequently led astray in their con- 
clusions. Of course it is beyond any man to grasp a subject in a}l its bearings, 
for, as we have seen, that would mean omniscience ; but he is the best scientist 
who can master the most of these relationships. 
I purpose in this paper to discuss a few topics in illustration of the interde- 
pendence of scientific concepts. 
Consider first the simple idea of motion. Think of a wheel of a moving car- 
riage. A chalk-mark on the tire is at rest in reference to that part of the wheel, 
moves in a circle in reference to the axle, moves in the curve of a cycloid in refer- 
ence to the horizontal plane; but the path of the chalk-mark is no longer a true 
cycloid if you remember the earth’s surface is spherical instead of plane. Again, 
referred to the plane of passage, the chalk-mark has a maximum velocity when 
it is uppermost; that is, the upper half of the wheel is going faster than the 
lower half: but referred to the wagon axle, the velocity is uniform. The velocity 
of the carriage may be five miles an hour if we conceive the roadway to be 
stationary ; but if we recall the rotation of the earth on its axis, the velocity at 
once jumps to a thousand miles per hour. Now think of the motion of the earth 
about the sun, and, if the time be early morning, to the thousand-mile velocity you 
must add another nineteen-mile-per-second speed. But we are not yet done, for 
the sun is hurrying through space toward the constellation of Hercules with a 
further velocity, guessed by some astronomers to be as much as sixteen miles per 
second, carrying with him the earth, our carriage, its wheel, and the chalk-mark 
on the tire. All things considered, what is the path of that chalk-mark? 
We speak of the dark Fraunhofer lines in the solar spectrum, which indeed 
are only dark by comparison with the much more brilliant adjacent field, and 
which examined independently may be demonstrated to furnish considerable 
light. Likewise sun-spots are ‘black’ when contrasted with the surrounding 
portion of thé sun’s disc; and yet their darkest areas outshine the caJcium light. 
