Stonehenge decoded

SIR – You report (June 21) that the builders of Stonehenge may have had a working knowledge of the Pythagorean theorem, 2,000 years before Pythagoras was born.

Prof Gerald S Hawkins, a British astronomer who worked in America, mentions this in Stonehenge Decoded (1965). He observes that the rectangle of the station stones, coupled with the various alignments discovered, would only work at the precise latitude at which the monument was built; 30 miles north or south would have produced a rhomboid and no alignments. He also put forward plausible explanations as to why there are 56 Aubrey holes, 30 Y holes, and 29 Z holes.

At the time academic archaeologists dismissed Hawkins’ research, as it spoilt their theories about priests, burials and sacrifices. It is good to see that he is gradually being proved correct. Jonathan Tucker

Burnham-on-crouch, Essex

SIR – In Ireland there is a structure that predates Stonehenge by at least 2,000 years. That is Newgrange, a prehistoric burial chamber so constructed that on the precise day of the winter solstice the sun’s rays shine through a hole in the roof and light up a domed burial chamber in the centre.

How the ancients managed to identify that date is certainly beyond my comprehension. John R Mcerlean

Elstow, Bedfordshire