ADDRESS ON RELATIVITY.

Press, Volume LVIII, Issue 17452, 12 May 1922, Page 11

ADDRESS ON RELATIVITY.

EINSTEIN'S RISE TO FAME.

THE THEORY OP A GENIUS.

(FROM OUB OWN correspondent, y LONDON, March 31. To the Students' Union of Birkbeck College, Lord Haldane exjilained "The Philosophy of Relativity." He said ho knew only a portion of .it, and that very imperfectly, but was strongly of the view. : that Einstein's, application'of a principle was only the particular application of a principle that went far beyond the doctrines of mathematics and physics, and that in days to coma relativity would.be recognised as having a much -wider meaning. | Einstein s doctrine was that space and time were relations between tiie observer and the thing observed, which altered with tho situation and conditions of the observer, and that . consequently , they varied according to that situation and those conditions. "Observe the consequences. Everyone of us, you thero, and I here, have oux own private space and time system. There is no such thing as objective space and time. Wo ciU'ry about with us our own systems of measurements, i.e., according to situation and conditions. We.all measure approximately the same way. The differences axe so Small , that they are negligible, but when you come to observe a distant star moving in the heavens thero may be enormous differences, and that is what Einstein found."

Einstein's Career. In the begining of the Twentieth Century, Einstein, < who had been a teacher in a Swiss secondary school, waß a clerk in a patent office in Zurich, and had already developed a genius for mathematics. The Swiss Government did not realise that —Governments were not apt to notice genius—(laughter)--but the observant Prussians in Berlin did, and sent a couple of experts to Zurich. As a result, the Germans offered him a Chair at JBreslau, whereupon the Swiss took him back, and after a good deal of competition, m which Holland took part, the Germans procured for him a Chair m Berlin. That was an instance of a youug manEinstein was not much over forty now —who had shot up through the sheer foroe of his gsi'jus. (Cheers.) Einstein was an extremely practical person, tie was a pereonal friend of his own, ana, after staying with him on the last occasion, hurried back to Berlin to calculate the mathematical equations lor a freezing machine, saying: "What is the good of having mathematics if you cannot help the democracy? 1 can give them cool "beer and milk at small expense." (Cheers and laughter.)

The Velocity of light. At the beginning of his career Einstein was faced with a new fac . said that everything m previous theories depended on the assumptio that space and time, measured by velocity of light, were unalterable, and unchanging, and independent ot the observer, and ho came to the c n elusion that that assampt.on was not justified. His doatrme was that space and time were a relation between t observer and the thing observed whicn altered with tho situation and condition of the observer, and was consoauently variable. The result was th.t each one of them was tneir own spaoe and time system. On the earth, that could make very little difference, as they all measured approximately in the same way, but vheft they came to the star 3 in the heavens there must be an enormous difference, and that was what Einstein meant. On going into mathematics he found that we had been measuring space and time with respect to our own condition, and that such measurements depended on whether the observer was moving or at rest

• Explaining that it was the velocity of light that determined timo and space. Lord Haldane said that it ho were looking at Big Ben he might see that between the hours of eight and nine the hour hand nad moved, say, two inches. But suppose he were onserving Big Ben, not from London, but from the sun, with a tremendous telescope, what would he see? The earth was moving round the sun at the rate of 70,000 miles an hour, and he would observe that tlis hour- hand had movrd its point not two inches, but 70,000 mile 6 plus two inches. That would bo. very perplexing— (laughter)—only he remembered that while the observer on earth was at rest the observer in the sun was not at rest, but moving round him at a huge velocity. As ai passenger stepped across a carriage u> reach his bag _ in a train passing through a station a porter on the station noticed that it took lmn about two seconds to go a yard, "but, ' said the portei, "ho is going in an express .travelling at sixty miles an hour: therefore, ho is moving at the rate ot ; sixty miles an hour plus a fraction. There was another porter in the sun who said, "Ho, ho, that porter said that passenger was going at sixty miles 3.11 hour plus; a yard. He was szoiotr past mo at sixty rnilos an hour, plus a yard, plus 70,000 miles." But then there was another porter in the Milky Way who scoffed, and said: "That ignorant porter in the sun thought 70,000 miles an hour would cover it "Why, the solar system is goin E at least 70,000 miles au hour past the point at which I am m the Milky Way." There was no end to put to the limit of space, added Lord Haldane. There might bo velocity .jeyonU velocity, and they were all relative to the observer. There was no such thing 'as au absolute, measurement of space. If they grasped the theory of relativity it m'ade them critical in the uso of their faculties ' and delivered them from many perplexities arising from assuming that there was only one way of comprehending things, whereas in truth there were many ways.