XXIX 



recent Foraminifera of Great Britain, after publishing a number of 

 shorter memoirs on the group. 



In 1851-2 Williamson made a careful study of the organisation of 

 Volvox Globator, and brought out facts as to the mode of connection 

 between its cells, which have only been verified by other observers 

 within the last few years. This was probably his best contribution 

 to recent botany. 



Shortly before this date Williamson had undertaken an investiga- 

 tion of a totally different kind, namely, the development of the 

 teeth and bones of fishes, which he considered in relation to the cell 

 theory. His results in this field were of great importance, and are 

 embodied in two papers published in the * Philosophical Transactions 

 of the Royal Society ' for 1849 and 1851. The value of these inves- 

 tigations was recognised by his election as a Fellow of the Royal 

 Society in 1854. 



Previously to this, in January, 1851, Williamson had entered the 

 ranks of official teachers of Science, by his appointment as Professor 

 of Natural History in the newly founded Owens College at Man- 

 chester. This was an arduous post, for the subjects to be taught 

 included three sciences : zoology, botany, and geology. At first he 

 found it possible to deal with this formidable task, by spreading his 

 complete course over two years, a wise arrangement under the cir- 

 cumstances, but one which the exigencies of the examination system 

 ultimately rendered impracticable. This led in 1872 to a division of 

 the duties of the chair, Williamson being then relieved of the geo- 

 logical part of the teaching by Professor Boyd Dawkius. The remain- 

 ing work, however, was still far too extensive for any one teacher, and 

 in 1880 a further division of labour took place. The late Professor 

 Milnes Marshall occupied the chair of zoology, while Williamson 

 retained that of botany, which he continued to hold till 1892. 



In addition to his strictly official work as Professor, Williamson 

 was one of the first two members of the staff, who, as early as 1854, 

 started evening classes for working men. In later years, he met 

 with extraordinary success as a popular scientific lecturer, more 

 especially for the Gilchrist Trustees, for whom he delivered some 

 hundreds of lectures during the period from 1874 to 1890. His 

 power of rousing and retaining the interest of great popular audi- 

 ences is described by those who have heard him as most remarkable. 



During a great part of the time at Owens College, Williamson 

 continued in active and successful practice as a physician. In the 

 midst of all his multifarious duties, as professor, popular lecturer, 

 and medical practitioner, he always found time for original scientific 

 work ; rarely has so busy a man done so much for the advancement 

 of science by actual research. 



So far, little has been said of the work of Williamson on fossil 



