592 



SCIENTIFIC NEV\^S. 



[June 22, iS 



poison is introduced into the human system by the bites 

 of mosquitoes, and whether homoepathic doses of certain 

 snal^e-poisons act as a prophylactic ? 



To those enthusiasts who think that the opening out 

 of the Shire and the Congo will cause an immense com- 

 merce to spring up, Mr. Drummond replies that it is 

 difficult to create new wants among the Africans, and, 

 secondly, that they have little to offer in exchange. 



The chapter entitled " The Heart Disease of Africa, its 

 Pathology and Cure," is illustrated by a map showing 

 the tracts followed by the slave-hunters, the regions 

 which they have entirely depopulated, and the districts 

 where the inhabitants are kept in constant peril. 



" The White Ant, a Theory," is the heading of a most 

 interesting chapter. The author shows that in certain 

 tropical climates the white ant — improperly so called — 

 is probably a more important soil-maker than the earth- 

 worm. His description of its operations in nest-building, 

 foraging, and constructing covert waj's is not in the least 

 exaggerated, and we think that he makes out a very 

 good case on the part of his neuropterous clients. We 

 must not forget that Darwin nowhere regards the earth- 

 worm as the sole soil-maker. 



Not less interesting is the chapter on " Mimicry," of 

 which Mr. Drummond finds many illustrations in the 

 ways of African insects. He gives full confirmation of 

 the observations of Wallace, Bates, and Belt, which he 

 had previously considered as somewhat highly coloured. 

 When he found that a wisp of h'ay, which had fallen 

 upon his coat, was a living Phasma — when he saw a 

 white splash upon a rock, which seemed simply a bird- 

 dropping, begin to move, and found that it had a head, 

 six legs, and a segmented body, he became convinced 

 not merely of the reality of insect mimicry, but of its 

 extreme closeness and accuracy. He avows that no 

 mere verbal description, no comparison even of dead 

 specimens, will convince the observer how hard such 

 creatures are to detect in their native situations. 



One peculiarity of tropical Africa does not seem to 

 have attracted the author's notice • — the comparative 

 monotony of its fauna and flora. When once we are 

 past the Sahara we find a multitude of the same forms 

 recurring in Sierra Leone, in the islands of the central 

 lakes and in Natal. What a contrast to South America 

 and Oceania ! 



Here, however, we must pause. We should gladly 

 follow Mr. Drummond in his wanderings on the Nyassa- 

 Tanganyika table-land did space permit. But we may 

 say in conclusion that " Tropical Africa " is at once a 

 very readable and a very instructive book — attributes 

 not always found in combination. 



A Manual of Phonography. By Isaac Pitman. London 

 Isaac Pitman and Sons. 

 We have received a new edition of this useful work, 

 which is in several respects an improvement upon the 

 original book — the examples being more numerous, and 

 the matter generally of a sufficiently explanatorj' character 

 for efficient self-instruction. It is not, however, easy to 

 understand why certain popular forms of long standing 

 should have been changed ; and it may be safely asserted, 

 at any rate as regards existing shorthand writers, that 

 the alterations will prove to be a dead letter. For the 

 sake of general convenience, it is obvious that a system 

 so widely adopted and so long in use should not be modi- 

 fied, unless in view of a far greater necessity than ap- 

 pears to exist. 



of l^aper^, %u\mt$^ nu 



GEOLOGICAL SOCIETY OF LONDON. 

 At the meeting on June 7, 1888, W. T. Blandford, 

 LL.D., F.R.S., President, in the chair, the following 

 communications were read : — 



" On the Sudbury Copper Deposits (Canada)." By 

 Mr. J. H. Collins, F.G.S. 



These deposits occur in Huronian rocks. The author 

 described two exposures, known as Copper Cliff and 

 Stobie, about eight miles apart. At the former the ore 

 was found in the face of a cliff of diorite about forty feet 

 high'. 



The ore exists in three distinct forms.: — 



1. As local impregnations of siliceous and felspathic 

 beds of clastic origin, in the form of patches and strings 

 of cupreous pyrrhotite. 



2. As contact-deposits of the same material lying 

 between the impregnated beds and large masses of diorite. 



3. As segregated veins of chalcopyrite and of nickeli- 

 ferous pyrrhotite, filling fissures and shrinkage-cracks in 

 the ore-masses of the second class. 



The author considered the first as original, or of high 

 antiquity ; whilst the two latter are due to segregation 

 produced either by intrusion of diorite, or by internal 

 movements. He compared these- deposits with those of 

 Rio Tinto of Devonian age, showing their similarities 

 and differences. At the latter place the intrusive masses 

 are quartz-porphyries, and the metallic deposits consist 

 mainly of bisulphide of iron. The ore-bodies in the 

 Canadian deposits are not so large. From the cupreous 

 pyrrhotite of Sudbury, rich though it be, compared with 

 the Rio Tinto ore, the copper cannot be so chiefly ex- 

 tracted by the wet method, and the ore is of no avail as 

 a source of sulphur. Nickel is everywhere present in 

 the cupreous pyrrhotite of Sudbury, and of no advantage 

 to the smelter. The differences above recorded are 

 probably not due to differences in the containing rocks, 

 since similar differences may be noticed in the pyritous 

 deposits of Canada, where the country - rocks are 

 identical. 



" Notes on some of the Auriferous Tracts of Mysore 

 Province, Southern India." ByMr. George Attwood, F.G.S. 



The author was employed during parts of 1886-7 in 

 inspecting a large area of mineral land in Southern India 

 supposed to be auriferous, and the paper contained the 

 results of his observations. 



I. Mclkolc Section. This section (in the Hassan district 

 of the province of Mysore), starting one mile west of 

 Melkote in a north-easterly directon, exposed gneiss, 

 mica-Echist, hornblende-schist, quartzite, talc, and 

 chlorite-schists, eclogite, and quartz veins, striking gener- 

 ally N. 20 degs. E., and having varying dips. The 

 eclogite was described at length, and special attention 

 was called to the flattening of the contained garnets, 

 which were probably originally almandite; other evi- 

 dences of great crushing were also noted. 



In this section and on most of the schistose lands of 

 Mysore a dull grey, nodular, and botryoidal calcareous 

 deposit, known as " kunkuc," is found in nullahs, on hill- 

 sides, and on the detritus of old gold washings, and it 

 was suggested that the contained lime was derived in 

 great measure from hornblende-schists. 



