Copy letter, JWL [John William Lubbock], RS [Royal Society], to M [Dominique Francois Jean] Arago Lubbock asks to trouble Arago: he would like to receive the observations of Brest tides as soon as possible and he asks Arago if he could have [Macedonio] Melloni acknowledge the receipt of his Rumford Medal money, as Lubbock must show end of year accounts. Lubbock would also like to have the measures which M. [Robert-Aglaé] Cauchoix employs for his two large object glasses. Sir John Herschel recommends a double convex crown and concave-convex flint as employed by [Joseph von] Fraunhofer, although he thinks that Cauchoix uses double convex and double concave, as does [George] Dollond. With two small marginal sketches of lens arrangements. 19 May 1835