Letter, from Henry Oldenburg to Johannes Hevelius Explains why the making of the lens for the telescope was delayed; details about the selling of his books with prices and the amounts spent on items which Hevelius required; that he would not be sending the telescopic tube because it was too expensive with discussion about the making of these tubes; that Hooke has not finished the telescopic sights; postscript about objective lenses 2 August 1669