Copy letter, from Sir John Herschel to Friedrich Wilhelm Bessel, dated at Slough Copy letter in John Herschel's hand. Requests Friedrich Wilhelm Bessel to send John Frederick William Herschel any observations of Gamma Virginis made by Friedrich Wilhelm Bessel. Anxious for these because of differences between John Frederick William Herschel's and Wilhelm Struve's measurements of Gamma Virginis. Provides John Frederick William Herschel's new determination of the orbital elements of this object. Thanks Friedrich Wilhelm Bessel for publications Friedrich Wilhelm Bessel sent. John Frederick William Herschel's brother-in-law, J[ames Calder] Stewart, may visit Friedrich Wilhelm Bessel. 17 April 1833