22 Annals of the Philosophical Club 



matical papers, he was one day using a camera lucida by the Lake 

 of Como, when the idea occurred to him of making its pictures 

 permanent. Wedgwood, indeed, had already produced evanescent 

 ' sun pictures ' on sensitized paper, so he adopted that method, 

 and had all but succeeded when Daguerre did this by another 

 process. Talbot, however, went on with his experiments, the 

 result of which was the so-called Talbotype, patented early in 

 1841, which soon ousted the daguerrotype. Then he devised 

 methods for taking instantaneous pictures and for photographic 

 engraving. Besides his successes in mathematics and photography, 

 he was a good archaeologist and among the first to decipher the 

 cuneiform inscriptions from Nineveh. Elected into the Royal 

 Society in 1831, he received a Royal Medal in 1838 and the Rumford 

 in 1842, and died at Lacock Abbey (his birthplace), Sept. iyth, 1877. 



PROFESSOR ADAM SEDGWICK, a geologist of real genius, was son 

 of a Yorkshire dalesman, born at Dent on March 22nd, 1785. From 

 Sedbergh school, after study under John Dawson, a self-taught 

 but first-rate mathematician, he went to Trinity, Cambridge, 

 graduated in 1808 as fifth wrangler, was elected a Fellow in 1810, 

 and appointed assistant-tutor five years afterwards. Ordained 

 in 1816, he was elected in 1818 Professor of Geology, though 

 hitherto he had not seriously worked at that subject. But he 

 began at once to travel for that purpose in Great Britain, and to 

 produce papers, becoming F.R.S. in 1830 and President of the 

 Geological Society in 1829. Beginning in southern and eastern 

 England, he then attacked the magnesian limestone and associated 

 red rocks of the north-east, after which he went with Murchison 

 (page 1 6) to examine the red sandstones on the western side of 

 Scotland. With him also, in 1829, he made a long journey through 

 Mid-Europe as far as Trieste, and worked at the Eastern Alps. 

 Important papers were the outcome of these studies, but he was 

 now becoming keenly interested in the problems offered by the 

 ancient rocks of Britain. With those of Cornwall and Devon he 

 had to some extent the help of Murchison ; in the Lake District 

 he worked single-handed, and in 1831 they attacked, though sepa- 

 rately, the difficulties of Wales Murchison working westward 

 from the Severn, Sedgwick in a more or less south-easterly direction 

 from the north-western coast. Papers, read from time to time, 

 announced their progress, till in 1839 Murchison published his 

 important book, The Silurian System. Further work in Wales 

 convinced Sedgwick that his friend had confused two distinct 

 sandstones. He communicated the results to the Geological Society, 

 and in 1852 read a paper criticizing a map of North Wales, issued 

 by the Geological Survey, which placed in the Silurian almost the 

 whole of the Formation which he had named Cambrian. The Society, 

 as Sedgwick thought, did not deal fairly with that paper, which 



