44<^ TkANSACTIONS OF S( ;ci i-:Tii':s. 



TRAXSACTIONS OF SOCIETIES. 



South Akricax Institltjox ok Engineers. — Saturday, April i^tli \V. 

 Ingham, M.I.C.E.. JNI.T.M.E., President, in the chair. — '" The Johannesburg 

 Municipal Electric Pozver Station " : J. H. Dobson. After a few preli- 

 minary remarks on the growth of population and area of Johanneslnirg, 

 whicl: now has a quarter of a million inhabitants, the author devoted the 

 first section of his paper to an account of the gas engine scheme, which 

 was initiated in 190.4, and. after some time of unsatisfactory operation. 

 abandoned in 1907. The present power station steam plant was then 

 exhaustively described, together with some account of the working results 

 and tests on various portions of the plant. During the last six years the 

 number of connections to the mains have increased from 5,720 to 16.091, 

 the total units generated from 12,694,367 to 26,426,072, and the total num- 

 ber <if street lamps from 5.340 to 7,000. 



Geolocic.m. Society of South .Afrtc.v. — Monday. April loth : P. A. 

 Wagner. B.Sc, Ing.D.. President, in the chair. — " The Karrao Rocks and 

 Later Sediments 'Xflrt':-JVcst of Buh-iwayo " : A. AI. Macgregor. A 

 description was .given of the sedimentary rDcks which lie ai)proximately 

 horizuntally in the country within a 50-mile radius north-west of Rula- 

 \vayii. These comprise : hrst, the Karroo ])eds, comprising the Forest 

 Sandstone, overlain apparently nnconformably by the Xyamandhlovu 

 Group of Basalts and Sandstones ; and secondly, sand and lateritic iron- 

 stoni.'. correlated with the Kalahari beds of Passarge, and alluvium prob- 

 alily (;f Quaternary age. none of which had ijreviously been systematically 

 dealt with. — ''Diamonds from the Moltcno Beds": Prof. E. 11. L. 

 Schwarz. On twn occasions the author had received wash from the 

 Moltcno beds, which contained Ijrilliant specks, showing, under the micro- 

 scope, all the characteristics of diamonds. These splinters were too 

 small for commercial tise, and were accompanied by red garnet, rutile, 

 kyanitc, epidote, ziron, monazite, anatase, tourmaline, and quartz, all of 

 similar size to the diamonds. 



South African Society of Civil Engineers. — Wednesdav, April 12th ■ 

 Prof. A. E. Snapc. M.Sc, A.:\I.I.C.E., M.R.San.I.. President, in the chair.— 

 "Maintenance icork on the Beira and Mas' onaland and Rhodesia Rail- 

 zvays " : J. Buchan. The total mileage of the railways concerned is 2,471 

 miles. One of the chief prolilems in past j'cars has 1)een th^' supply of a 

 good class of nati'c lal)our. Steel sleepers were used for the track to 

 prevent damage by white ants. Round and t^at top rails of 60 lb. per yard 

 were laid. The maximum gradient is i in 50, and the minimum radius of 

 curvature is five chains. The heaviest engines in use are of i20:j tons. 

 The quality of water obtainable is usually good, but two borehole waters 

 near Wankie proved unsuitable ; one of these had to be abandoned and a 

 softening process applied to the other. The maximtim speed has been 35 

 miles per hour, and the annual costs of maintenance £75 to £So per mile on 

 main lines, and about £50 per mile for branches.-" t^';;;/ Transition Curves": 

 F. W. Scott. The author described a simple method for obtaining the 

 data for staking out the " cubic parabola ' as used for transition curves, 

 and exhibited tables compiled in a compact form for this purpose. 



South African Association or Analytical Chemists. — Thursday, 

 April 13th : J. Moir, M.A., D.Sc, President, in the chair. — '' Tlie determi- 

 nation of the true reaction of waters by means of mixed indicators" : 

 Dr. J. Moir. The author described the use of methyl red and o. — 

 naphtholphthalein in place of meth}! ofange and phenolphthalein for the 

 determination of the true reaction of waters. — ''A simple apparatus for 

 metallograplric H'ork " : W. O. Andrews. 



Chemical, Metallurgical, anii Mininc; Society of South Africa. — 

 Saturday, April 15th : Prof J. A. Wilkinson, M.A., F.C.S., Vice-President, 

 in the chair. — " Concrete shaft equipment at the Bantjcs Consolidated 

 Mines " : W. W. Lawrie and G. Hildick Smith The concrete shaft 

 equipment in the Central Shaft of the Bantjes Consolidated Mines con- 

 sists of concrete shaft rail foundations as continuous stringers through 

 the shaft. The dimensions of these concrete stringers were explained, 

 and their materials and method of construction described, as well as the 

 method of laving rails on the stringers. 



