The Birmingham age-herald., 1921-04-10

Your correspondent has, therefore, ar ranged for an interview with the emi- nent scientist in an attempt to bring the subject clearly before the public. Un- fortunately the interview has not yet taken place, owing to the fact that the window leading to Dr. Einstein's room from the fire escape was locked but no contemplating man would let technical detail like that interfere with the writ ing of a personality story; so here is an account of the interview which will take place early next week.
 PLAYING WITH MATCHES
 As the reporter was shown into the temporary study he was surprised to see the famous discoverer sticking matches into an orange. Dr. Einstein was also somewhat surprised to see the reporter and in his embarrassment held up the fruit, saying, by way of open- ing the conversation
 Hello! Doesn't that look like the sun when do that to it?''
 The reporter, still irritated from an ar gument with the elevator boy outside, said no he didn't think that looked like the sun at all.
 Cordial relations thus being established, Dr. Einstein was asked if he would kind Iy explain the theory of relativity in few words.
 Nothing elaborate" he was told, just something that we can so back and tell the boss
 T am glad you asked me- said pr. Einstein 'TThe theory of relativity is easily explained. Have you match?'
 A match was furnished and close at tention paid. The scientist struck the match on the box especially prepared for the purpose, and with it's flame light ed the tobacco in a pipe which lab- oratory attendant brought to him.
 There" he said. now l can talk better"
 You know the rate at which light travels through space?" the doctor in- quired.
 DOTES ON SPEED
 Do I?'. asked the reporter. ''Oh, boy!'
 Well, that's that. Let us now think of something else Do you like to ride on railway trains?'
 'I just love it." replied the reporter.
 There is one that leaves here in Is minutes" said pr. Einstein. "I think that you can make it if you don't wait for the elevator"
 But you haven't explained the theory of relativity to me-" protested the news paper man.
 T think did" said the scientist, but you weren't listening. It doesn't take long, and if you aren't paying close at tertion you are likely to miss it. I'll do 1t again for you"
 The reported drew his chair up closer in order not to lose anything.
 Let us take the example of railway train again. stand at the window of a day coach at time when the train is moving at a uniform rate of speed and I drop a stone out on the embankment
 shame on you" sai6 the reporter
 .sDisregarding the influence of air re- sistance (which I always do when I am alone). I see the stone descend in straight line pedestrian who observes my action fro mthe footpath, however. parabolic curve. You know what a para bola isr'
 Sure, the parabola of the foolish vir- gins, for example"
 'All right, we'll let that pass. What l want to know is do the positions trav- ersed by the stone lie in reality on straight line or on 8 parabola? More over what is meant by motion in space?"
 .I'n bite" said the reporter. 'what?"
 Space is something that we cannot conceive of," laughed the Herr Doktor. We shall therefore speak only of mo tion relative to practically rigid body of reference'
 .-rhat suits me-" agreed the inter viewer.
 VERY SIMPLE NOW
 If instead of body of reference we insert system of co-ordinates,' which is a useful idea for mathematical descrip- tion, we are in a position to say: The stone traverses a straight line relative to a system of co-ordinates rigidly attached to the train, but relative to system of coordinate rigidly attached to the ground, it describes a parabola.' With the aid of this example it is clearly seen that there is no such thing as an inde- pendently existing trajectory. but only trajectory relative to particular body of reference"
 T understand all that said the re- porter, but how do you know when 1t