Letter, from Charles Piazzi Smyth to Sir John Herschel, dated at Royal Observatory, Cape of Good Hope Autograph letter signed by sender. Sends John Frederick William Herschel observations of Comet of 1843; disappointed with Cape Observatory's records of the comet. Oversees Observatory in absence of Thomas Maclear, who is at Zwartland for meridian survey. Lists and describes instruments in use at Cape Observatory. Discusses sources of error. 9 March 1843