Letter, from William Rutter Dawes to Sir John Herschel, dated at Wateringbury, Maidstone Autograph letter signed by sender. Would like his opinion on a divided glass, double image micrometer before he submits it to an optician. George Dollond has lent him some divided glasses of long focus. Would like to borrow G. B. Amici's micrometer if John Frederick William Herschel could spare it. 23 December 1854