Letter, from John Tyndall to Sir John Herschel, dated at Royal Institution Autograph letter signed by sender. Regrets 'stupidity' of Italian post office, which lost note sent to John Frederick William Herschel suggesting reprinting of passage from Treatise Astr. of 1833 on operations of sun in second edition of John Tyndall's book. Also wants to publish John Tyndall's 'extremely philosophical views' on muscle contraction. 17 September 1864