Letter, from Henry Oldenburg to Robert Boyle, dated at London Concerning experiments to show weight of tin and copper and then mixed with air and then water; concerning Steno's experiment of 'binding up the descending artery from the head'; transcribes a letter from Pierre de Carcavy (in French) about the aspirations of the French academy of Science (see EL/C1/46 for original); concerning the movement of the French army 25 February 1668