Letter, from Henry Oldenburg to John Downes, dated at London Thanks Downes for his communications and proposal of monitoring different degrees of heat and cold between Rome and London; concerning an experiment to show the effects of viper's bite on dogs and the application of the serpent stone as an antidote; reminds him to obtain information about philosophical developments in Italy; that the Society was working on the laws of motion and that the Parisian academy had published some anatomical observations 4 May 1669