Copy letter, regarding Christian Huygens' work, from [James Gregorie] to the publisher Gregorie replies to the exchange of letters printed in the Journal des Sçavans on 2 July 1668, in vindication of Christian Huygen's works 'Vera Circuli' and 'Hyperola Quadratura'. Copy of CLP/1/22. This was Henry Oldenburg's copy. Subject: Mathematics Published in Philosophical Transactions as 'An extract of a letter of Mr. James Gregory to the publisher, containing some considerations of his, upon M. Hugens his letter, printed in vindication of his examen of the book, entitled Vera Circuli & Hyperbola Quadratura'. 1668