HARDWICKE'S SCIENCE-GOSSIP. 



43 



Birds of the Isle of Man. — The hon. sec. 

 of the recently founded Isle of Man Natural History 

 Society, Mr. Philip Kermode, is engaged in a most 

 useful and laudable work, that of cataloguing the birds 

 of the island ; and at a recent meeting he presented a 

 list of all well-authenticated species noticed up to 

 that time, which amounts to one liundred and forty- 

 two species. The list includes the snowy owl, golden 

 oriole, mountain finch, hoopoe, grey plover, bittern, 

 grey phalarope, and Manx shearwater. The black 

 guillemot breeds near Peel, and (it is said) also in 

 the south of the island. 



Norwich Science-Gossip Club.— This flourish- 

 ing society recently celebrated its tenth anniversary, 

 and now publishes abstracts of the useful various 

 and frequently elaborate papers read at the fortnightly 

 winter meetings. 



The Evolution Theory. — At a recent meeting 

 of the Zoological Society of London, Professor Huxley 

 read a paper on the Application of the Laws of 

 Evolution to the Arrangement of the Vertebrata, 

 and particularly with reference to the Mammalia. 



BOTANY. 



The use of Fungus-Growths to Destroy 

 Insects. — In the " American Naturalist," Professor 

 A. N. Pi'entiss has a paper on the above subject. 

 After reviewing the observations made by previous 

 writers, and detailing the direct and indirect results 

 of several experiments, Mr. Prentiss concludes that 

 the result of these experiments, as a whole, indicate 

 plainly that yeast cannot be regarded as a reliable 

 remedy against such insects as commonly affect 

 plants cultivated in greenhouses, rooms, and parlours. 

 Moreover it is more than probable that the yeast 

 would injure many kinds of plants, by spotting and 

 soiling the leaves, and inducing fungoid growths 

 upon the jars or soil in which the plants are grown. 



HELiOTROnsM. — On p. 132 of Professor Ramsay 

 McNab's Physiological Class Books, this theory is 

 laid down : " Light exercises a retarding iniluence 

 on growth." This influence, he proceeds to explain, 

 causes the bending of plants to the light ; but, in the 

 course of the next page, this sentence occurs : " The 

 side of the organ away from the source of light, 

 receiving less light than that turned towards it, has 

 its growth retarded." Surely this is a manifest contra- 

 diction of the theory laid down in the preceding page. 

 The part away from the light would have its growth 

 accelerated by the want of light, and such is really 

 the fact, for when the stem bends to the light, the 

 part away from the light is longer than the part 

 turned towards the light, for, if two curved lines both 

 turned the same way, the outside line is the longest. 

 Is it a misprint, or a misinterpretation on my part ? — 

 J. P. K. 



DEVELorED Primulas. — When I brought my 

 specimens home from Thurso, I was unable to name 

 them myself, but was told they were P. farinosa, and 

 I quite thought they were, until I saw Mr. A. Craig 

 Christie's remarks in your December issue. After 

 examining them again I have concluded they must 

 be P. Scotica (Hook.). Hooker says P. Scotica is 

 "perhaps only a sub-species of P. farinosa, but 

 smaller." I suppose the sessile umbel is not common 

 in either case. — W. K. McGhie. 



'GEOLOGY. 



The Geology of East Central Africa. — A 

 recent number of " Nature" contained a short article 

 on the above subject, by Mr. Jas. Thomson, fellow- 

 traveller with the late INIr. Keith Johnston in the 

 Geographical Societies' African exploring expedition. 

 Speaking of the route to Nyassa and Tanganyika, 

 Mr. Thomson refers first to the low-lying country 

 bordering the eastern coast of Africa, which is formed 

 of two or three raised beaches, consisting chiefly of 

 brick-red sands and clays overlying coral rock. The 

 former have been derived by denudation from the 

 coast ranges. The sands are of value as containing 

 the well-knovi^n "gum copal." Geologically, these 

 formations are recent, as none of the insects found 

 embedded in the copal are extinct. The next forma- 

 tions found imply an immense gap in the geologic 

 record, being evidently of Carboniferous age, thus 

 indicating the immense period during which Central 

 Africa has been dry land. These formations extend 

 to the base of the mountains, and we pass abruptly 

 from them to highly metamorphosed rocks, consist- 

 ing of schists, gneiss, and hornblende, whose exact 

 place in the geological series is doubtful. These 

 form the mountain range flanking the great central 

 plateau which extends from Abyssinia to the Cape, 

 and rises to a height of 7000 feet. Leaving this 

 range we next pass over a great stretch of granitoid 

 rocks, extending to near the lakes, and marked by 

 undulating hills and valleys. This tract is terminated 

 by an abrupt rise, forming apparently a second and 

 higher plateau. The sudden change in level, to- 

 gether with the alteration in the internal structure, 

 and the presence of intrusive rocks at the base of the 

 mountain, seem to point to the existence of a fault 

 of considerable magnitude. The rocks composing 

 this high tract consist mainly of clay slates. On 

 approaching Lake Nyassa we observe evidence of 

 much disturbance, till at about ten miles from the 

 lake we come upon the ancient pipe of a volcano, 

 and about five miles farther on enter amongst a 

 series of volcanic porphyritc, tuffs, and agglomerates, 

 forming jagged peaks, sharp yawning valleys, and 

 irregular rocks, notched sides. The series of vol- 

 canic rocks, forming the magnificent mountains round 



