xxiii 



In 1859 he commenced, in conjunction with Dr. Sonder and with the 

 assistance of the Cape Government, a complete description of the flowering 

 plants and ferns of South Africa, in a work entitled " Flora Capensis," the 

 chief share in the labour of which fell to Dr. Harvey. As a companion 

 to this he also commenced a series of illustrations under the title "Thesaurus 

 Capensis.'^ Neither of these works did he live to see completed. 



In 1856, the Chair of Botany in the University of Dublin becoming va- 

 cant through the removal of Professor AUman to Edinburgh, Harvey was 

 chosen to fill it, and about the same time he was appointed lecturer at the 

 Irish Museum of Industry. 



Unhappily his unceasing labours began to tell upon his health ; and 

 though he recovered from a severe illness which prostrated him in 1861, 

 his condition in 1864 became so alarming that he was obliged to pass the 

 following winter and spring in the south of France. The improvement he 

 experienced there was, however, but temporary ; and after another winter 

 spent at Dublin in painful attempts to finish the works he had begun, he 

 removed to Torquay, where he died, May 15, 1866. 



He was thus cut off before he could receive the full acknowledgment 

 of his many services to science. He had, however, achieved a great repu- 

 tation as a botanist, and on his own especial subject of Algse he was admitted 

 to be the first authority. He was an accurate and careful observer ; the 

 numerous illustrations, all drawn and lithographed, and many coloured, by 

 his own hand, are evidence that he spared no pains to make his works 

 trustworthy and sure, while the personal expense and risk to which he ex- 

 posed himself both in his exploring expeditions and in his literary under- 

 takings, testify to his devotion to science. He was as modest as he was 

 meritorious, and his personal character endeared him greatly to his friends. 

 His election to the Royal Society is dated June 3, 1864. 



Percival Norton Johnson died on the 1st of June, 1866, aged 73. 

 He was the only son of John Johnson, at one time the only commercial 

 assayer in London ; and after working with his father for some years, he 

 estabhshed himself in Hatton Garden half a century ago. 



He rapidly rose to the highest eminence as an assayer and metallurgist ; 

 and his opinion was so much sought after that he could hardly get through 

 the work which crowded upon him. 



It is not a little remarkable that the extreme accuracy of his assays was 

 made a ground of objection to them. He for the first time reported the 

 exact amount of gold and silver in the specimens submitted, whereas, before, 

 the quantities had only been stated approximately ; and this was not 

 relished by the buyers of bullion, inasmuch as contingent advantages in buy- 

 ing upon exactly known value were not so great. Upon this being represented 

 to him by the merchants, he at once stated that he was willing, if required, to 

 purchase all bars upon his own assays ; and this was the reason of his taking 



