374 TRA.VSAITIONS OF SOC IKTIES. 



iiuluclidn cnil was reviewed, its suhsequeiit clevelupnient traced, tlie con- 

 struction and operation of the modern type of apparatus referred to. and 

 some of its applications recounted. 



Geological Society of S(juth Africa. — M<.)nday. December i8tli : P. A. 

 Wagner, B.Sc, Ing.L).. President, in the chair. — " Gra/'hitc-bcariiig xeno- 

 liflis from the Jayersfuntcin Diamond Mine :" Dr. P. A. "Wagner. 

 Xodular xenoliths of the cognate type, presenting in their mineralogical 

 composition an extremely wide range of variety, are rather abundant in 

 the blue-ground and Kimberlite vi the Jagersfontein Mine. .Among them 

 nodules containing graphite seem to be by no means uncommon. Two 

 specimens were described by the author, the contained graphite being" 

 identical in physical properties with the graphite found in a garnet-pyrox- 

 ene nodule from tlie Premier Mine, described by the author in 1911. — 

 " The altenitioii of the dolomite at the Xoriheni limezi'orks. near Pot- 

 iiietersrust " : Prof. R. B. Young. The rock quarried at the limeworks 

 belongs to the Dolomite Series, and is normally a magnesian limestone, 

 containing approximately 52 per cent, of calcium car])onate, wdiile the 

 rock quarried contains more than 90 ])cr cent. The changes which the 

 rock had undergone were indicated, and an ex])lanati>in (if its abnormal 

 composition was offered. 



•Monday, January 29th: P. A. Wagner, B.Sc, Jng.D., President, in the 

 chair. — "Some /problems in South Afriean* Geology'' : (Presidential 

 address) Dr. P. A. Wagner. Four problems, whicli have, in the past, 

 .greatly exercised the minds of South African geologists, were discussed 

 in the light of the latest investigations. These were: (1) The problem 

 of the auriferous conglomerates of the Witwatcrsrand, ( 2 ) The genesis 

 of the diamond; (3) Is the diamond susceptible of alteration under the 

 influence of the agencies operative or specially active at or near the earth's 

 surface? {4) The salt ])an on the farm Zoutpan, Xo. 467, north-north- 

 wesl of Pretoria. 



SorTH Afkua\ .\s! (I ■[ \tio\ ok AwM.vTic m. CiiKNFisTS. — Tluirsdav. 

 Fe])ruary 15th. — J. McCrae, Ph.D.. I'M-C. Vice-President, in the chair. — 

 "Blast funiaee possibilities in South A/ric-d'' .R. V. Crake. The author 

 instituted a comparison between the materials used in Sc<itland fiu* th..' 

 manufacture of pig-iron with those available in Soutli .\frica. and 

 arrived at the conclusion that with certain adaptations it was possible to 

 start a blast furnace industry, and that the time is opi)ortune. — " .\ on- 

 routine steel analysis" : W. ( >. Andreiws. .\ review of various methods of 

 steel analysis useful in laboratories wiure such analyses are only occa- 

 sionally required. 



Chk.mkal, Mkiallckgii \l .\.\ii Mi.M.Nd SiK iKTv OK Sociii .\frica. — 

 Saturday. February 17th: Prof. J. .A. Wilkinson. M..\., I'.C.S., President, 

 in the chair. — " Xezv Apf>lieations of 'l'hywol[>hthalein and Xaftholphlha- 

 lein. including Ra/^id Methods of Analysing Limestone and Ammonium 

 Salts": Dr. J. Moir. Three analytical methods were described: (a) A 

 rapid method of analysing limestone by titration. The acixl equivalent 

 of the CaO and MgO together are iirst deternn'ned, and the CaO subsc- 

 fpiently found by subtracting the MgO, whose determination is based on 

 the fact that magnesium hydrate, when coagulated by boiling, ceases to 

 affect thymolphtlialein, ;illhough it still colours i)!KMiolphthalein. (b) Xew 

 method oi determining amnninium ^alts by titration. By this method 

 annnonium may be determined in its neiUral salts when present in explo- 

 sives, fertilisers, etc:, without distillation. The solution is titrated with 

 sodium hydrate in presence of thymoIi)hthaIein, whicii turns blue when the 

 equivalent of the ammonia present has l)een added, the indicator remain- 

 ing unaffected by the annnonia set free. (r) Determination of true 

 neutrality in waters l)y means of mixed indicators. The mixture recom- 

 mended comprises methyl red and a-nap]itb()lo|ihthalein. This mixture will 

 detect 1 part of H..S()< and 2 |>arts of Ca(()II )■.. in i.ono.fjoo p.irts of water. 



