Letter, from Giovanni Antonio Plana to Sir John Herschel, dated at Turin Autograph letter signed by sender, with annotations by recipient. Is preparing a paper on planetary perturbations, which Giovanni Plana would like to send to the Astronomical Society for publication. Comments on John Frederick William Herschel's ideas on the subject of perturbations. Would the paper being in French be a problem? Comments on Henry Kater's method for finding the zero point in his meridian circle. 27 May 1825