Extract, 'A relation of the great effects of a new sort of burning speculum lately made in Germany' by unknown author This extract from the Acta Eruditorum of January [1687?] describes a concave burning speculum which the author had made in Lusace [Lusatia, a region situated in modern Germany and Poland]. Subject: Scientific Instruments Published in Philosophical Transactions as 'A relation of the great effects of a new sort of burning speculum lately made in Germany: taken from the Acta Eruditorum of the month of January last: being a letter from the inventor to the authors of that journal'. Read to the Royal Society on 22 June 1687. [1687]