ture difference immediately. We put the accumulator up in his cellar,
the accumulator being on a table, and a control thermometer hanging
about 3 or 4 feet away in the air. After some time he and I could both
see that the temperature above the accumulator was higher by about I
degree than the temperature of the surrounding air. We were both very
glad. He wanted to keep the accumulator for about 2 or 3 weeks and
then write to me. He said he wished to observe the continuity and the
average of the temperature difference. After about 10 days he wrote me
a letter. The letter stated: He had observed the existence of the fact
of the temperature difference on the accumulator for several days. Please
remember that he, as well as I, thought such a fact to be quite ex
traordinary-according to his words "a bomb in physics." So he had
observed the fact and affirmed it, but now comes that which I have
experienced with physicists and other natural scientists again and again:
First they deny the fact. When I demonstrate the fact and they cannot
deny it any longer, then they try to explain it away by some wild
interpretation. That happened, not with Einstein but with his assistant.
I stress again the fact that the possibility of a continuous temperature
difference without any visible source of heat seemed impossible to
Einstein. Well, now it comes: The assistant, apparently some wise guy,
knew all the answers. He told Einstein that in cellars there is a "con
vection of heat from the ceiling to the table top," and that this must be
the cause of the phenomenon which could no longer be denied. Now,
it is a law in scientific research that, when you have to confirm a fact
and you propose a different explanation of that fact, you are obliged
to control your own objection. Einstein's assistant did not do that. He
simply "objected" without proof. Einstein took the trouble, as he wrote
in his letter, to take the accumulator apart and he discovered that there
was a temperature difference between, above and under the table. The
fact, mind you, had not been known to Einstein. It seemed to confirm
the objection of the assistant, but there were only two ways of finding
out whether that objection was correct or not.
Now I shall pause for a moment. The answer is in the next few lines.
I want you to think for yourself what you would have done in order to
find out whether the temperature rise on the accumulator was due to
heat convected down from the ceiling or not.
Here is the experimental answer:
a) You simply take the control thermometer which was in the free air
and put it above the table at the same height as the thermometer above