Vegetation in the Canary Islands 235 



with very brilliant crystals of the cubic system, not more 

 than o-oi inch in diameter. So far as he remembered, but 

 he was not certain, thej^ scratched glass. An expert, to 

 whom M. Gassiot had shown them, said they were too 

 small to give conclusive evidence, but he saw no reason why 

 they should not be diamonds. All were used up in applying 

 tests. He had intended to repeat the experiments, but 

 soon afterwards he left the London Institution and returned 

 to active practice at the Bar. He had, however, done so at 

 his own house, with small batteries, but the only result was 

 a black deposit on the negative electrodes. 



May lyth, 37oth meeting. Mr. Ball, who had recently 

 visited the Canary Islands, made some remarks on their 

 flora, which is remarkable for the large number of endemic 

 plants, not growing in any other part of the world. Of 

 about 400 described species, some inhabit all or several of 

 the islands, but the majority are confined to a single island, 

 and this is generally Teneriffe. Perhaps all these may not 

 be true species, but we might safely say that the Canary 

 Islands produce 300 such species, besides about 50 species 

 common to them and Madeira, and in some cases also to 

 the Azores, but not known elsewhere. Among the species 

 strictly confined to the Canaries are several groups which 

 give a very special aspect to the vegetation, nine of the 

 genera being elsewhere unknown. Among the former is 

 the Sempervivum, of which 60 species (possibly 40 of them 

 quite distinct) have been described. An allied species 

 had been found by Sir J. Hooker and himself in the Great 

 Atlas and a shrubby Sempervivum near Mogador ; so one 

 might suppose this group of plants, which has multiplied 

 so greatly in the Canaries, to have an African origin. This 

 may be said with more confidence of the cactoid Euphorbiae, 

 which are so marked a feature in the Canarian flora, and of 

 the genus Sonchus, about 10 species of which are peculiar 

 to those islands ; there are also three African genera, 

 excluding the groups already mentioned, which are peculiar 

 to the Canaries. We know too little of the African coast 

 for the 15 of latitude between the mouth of the Sus river 



