The fourth part of a series on the expedition on board HMS 'Himalaya' to observe the total solar eclipse in Spain on 18 July 1860. The papers begin with comparisons of chronometers and work on thermometers by F.S. Adams. This is followed by observations of the eclipse at different stations in Northern Spain by D.A. Aquilar; G.B. Airy; W. Airy, including a map of the stars' positions during the eclipse; H.S. Atwood; J. Beck; W. Beck; J. Bononi, in the form of a diary and including a watercolour; J. Breen, with a drawing; J. Buckingham; M. Burland; E. Byrne; H.S. Ellis; and T. Chevallier. There are also longer papers written by C. Brenniker, in German; A. d'Abbadie; W. De La Rue, in 'The Photographic Journal', with descriptions of the methodology and techniques used in photographing the eclipse, as well as two photographs; and Dr C. Fearnley, in German, with a version translated into English. There are a number of maps of the eclipse, including its path across Algiers, and pictures of the eclipse on a treated linen fabric. There is also a comparative account by the U.S. Coastal Survey and its many observers, including diagrams and three photographs.