TRANSACTIONS OF SOCIETIES. 257 



among children under ten T had the greatest difficulty in obtain- 

 ing any pure specimens of their race. White blood is traceable 

 somewhere in the parentage always. 



Old people of any intelligence are few, and they alone know 

 anything of tribal lore. The Hottentot himself says he has been 

 absorbed into a new condition of things, and it takes him all his 

 time to keep abreast of the tide. An onlooker sees that he is not 

 keeping abreast, and never will for all his struggle. 



The material for further investigation is thus no longer to be 

 had, and I had perforce to be content with the remnants I had 

 been able to gather. On some lonely farm, perhaps, some old man 

 or some old woman may still be able to add to the collected facts, 

 but the time for further systematic scientific work is past. 



TRANSACTIONS OF SOCIETIES. 



Geological Society of South Africa. — Monday, March 23rcl : D. P. 

 McDonald, M.A., B.Sc, President, in the chair. — " Outlines of the geology 

 of German South-west Africa "' : Dr. E. Rimann — " On the occurrence 

 of the Brazilian trilobite Pcnnaia in the Bokkeveld beds": Prof. S. J. 

 Shand. Clarke, in his monograph on the Devonian fossils of Parana, 

 erects three new genera for the BraziHan representatives of the Metcp- 

 cryphaeus group of the Phacopidce. One of these new genera, Pcnnaia. is 

 known to Clarke only as a Brazilian genus. The author described a new 

 species, the ilrst of the genus to be recognised in .South Africa, having 

 been found by Mr. R. A. Page on the farm Osplaats in the Hex River 

 Valley. For this the name Pcnnaia africana is propofsed. — "Note on 

 graphite coated diamonds from the Premier Mine": Dr. P. A. Wagner. 

 The author described four well-formed diamond crystals, coated with a 

 thin film of graphite, by which they were rendered black and opaque. 



South African Society of Civil Engineers. — Wednesday, April 8th: 

 F. O. .Stephens, M.I.C.E., President, in the chair. — '' Ferro-concrete works 

 at Mossel Bay and Knysna ' : F. W. Waldron. A description was given 

 of a ferro-concrete jetty at ]\Iossel Bay for the larding and shipping of 

 goods into lighters, and of a similarly constructed wharf at Knysna ; also 

 of an elevated circular tank capable of containing lo.ooo gallons, and of 

 the casting and laying of a number of reinforced concrete pipes for surface 

 water drainage at Mossel Bay. 



Royal Society of South .\frica. — Wednesday, April 15th : S. S. 

 Hough, M.A.. F.R.S., Vice-President, m the chair. — " Note on a theorem of 

 Ph. Gilbert, regarding the differentiation of a Special Jacobian " : Dr. T. 

 Muir.^" Note on Rosanes' Functions, resembling Jacobians " : Dr. T. 

 Muir — " The Triple Stellar System t, Virginis and S 1757 " : R. T. A. 

 Innes. These stars, although a considerable distance apart, constitute a 

 system, as they are moving through space with ahnost identical velocities 

 and directions. — " A Curious Mosquito '" : G. A. H. Bedford. — " On the 

 porosity of the rocks of the Karroo System " : Dr. A. L. du Toit. 

 Determinations were given of the porosity of 90 rocks, the majority being 

 from borehole cores. It was found with respect to the three-fold division 

 of the Beaufort beds that the mean porosity of the sandstone was 2.9 % 

 for the lower, 5.2 % for the middle, and 5.5 % for the upper division. The 

 figures for the Transvaal phase of the Karroo were much higher. The 

 efifects of weathering in increasing the porosity were discussed and 

 analysed.^'' A Note on the Temperatures of the air observed at Mochudi." 



