158. HYGINUS.--Crater-pit 3·7 miles. Remarkable cleft runs through it; visible with 2-inch: connected with Ariadæus rill to W., which also an object for a 2-inch. Dark spot to N.W. on Mare Vaporum named Hyginus N. Has been suspected to be new formation. Plate XII. Seventh day. 168. ERATOSTHENES.--Fine ring plain at end of Apennines; 38 miles. Terraced wall 16,000 feet above interior, which is 8,000 feet below Mare Imbrium. Fine central mountain. Plate XIII. Remarkable contrast to 148 Stadius, which has wall only 200 feet, with numbers of craters on floor. Ninth and tenth days. 175. HERODOTUS; 176. ARISTARCHUS.--Interesting pair. 175 is 23 miles; 4,000 feet. Floor very dusky. Great serpentine valley; most interesting object. Easy with 2-inch. 176 is most brilliant crater on moon; 28 miles; 6,000 feet. Central peak very bright. Readily seen on dark part of moon by earth-shine. Plates XII., XIII. Twelfth day. 188. LINNÉ.--Small crater on M. Serenitatis near N.W. end of Apennines. Suspected of change, but varies much in appearance under different lights. Visible on Plate XVII. as whitish oval patch to left of end of Apennines. Seventh day. 191. ARCHIMEDES.--Fifty miles; 7,000 feet. Floor very flat; crossed by alternate bright and dark zones. Makes with 189 and 190 fine group well shown Plate XVII. Eighth day. 208. EUDOXUS; 209. ARISTOTELES.--Beautiful pair of ring plains. 208 is 40 miles. Walls much terraced; 10,000 to 11,000 feet; 209 is 60 miles; 11,000 feet. Plate XVII. Sixth and seventh days. 210. PLATO.--Great walled plain; 60 miles; 7,400 feet. Dark grey floor, which exhibits curious changes of colour under different lights, also spots and streaks too difficult for small telescope. Landslip on E. side. Shadows very fine at sunrise. Plates XII., XIII. Ninth day. 211. PICO.--Isolated mountain; 7,000 to 8,000 feet. S. of 210. Casts fine shadow when near terminator. Ninth and tenth days. 228. ATLAS; 229. HERCULES.--Beautiful pair. 228 is 55 miles; 11,000 feet. Small but distinct central mountain. 229 is 46 miles. Wall reaches same height as 228, and is finely terraced. Landslip on N. wall. Conspicuous crater on floor. Plate XI. Fifth day. APPENDIX II