Letter, from John Flamsteed to Henry Oldenburg, dated at Derby Discussing the calculi of Eramus Reinhold, Christianus Severinin Longomontanus and Philip Lansberg, which were sent by Hecker; discussing calculations for the transit of Mercury in April 1674 and October 1677; predictions from the ephemerides of Hecker for the year 1672 are attached Read to the Royal Society on 2 April 1673 17 February 1673