68 TKANSACTIOXS OF SOCIETIES. 



Ululated acid ore slime in order to ascertain the rate at which gold dis- 

 solves in the cyanide solution- The conclusions arrived at were that 

 success depended on maintaining a high alkalinity during the first three 

 hours of aeration, and that lime should be added to the slime before 

 treating with cyanide solution, so as to form a better protection for the 

 free cyanide ; also that lead acetate, when present, resulted in a better 

 extraction of the gold. As to the rate of solubility of the gold in the 

 accumulated slime in cyanide solution, more than 50 per cent, of the 

 gold in the ore slime was found to pass into solution in the first hour. 



South African Institute of Engineers — Saturday, July 8th : Mr. 

 F- H. Davis. President, in the chair. — "A system of soapy water lubri- 

 cation for air cylinders " : J. B- Roberts. The author, after pointing 

 to the fact that compressed air, though the safest means of transmitting 

 power, became actively dangerous under certain conditions, said th;it 

 explosions in air compressors were becoming more prevalent. The 

 causes of this were the presence of an explosive mixture, and an air 

 temperature sufficiently high to ignite it, inferior lubricants being amongst 

 these causes- Soapy water, if used systematically, is claimed to have 

 the effect of preventing the deposition of carbon in the compressor 

 cylinders and elsewhere, and so eliminating the possibility of flashing. 

 The compressed air would thus also be free from carbon monoxide and 

 other foul gases, and ensure a better atmosphere at the exhaust- The 

 method of mixing the soapy water and applying it was then detailed- 



South African Society of Civil Engineers- — Wednesday, July 12th : 

 Col- G- T- Nicholson, M-I-C-E-. President, in the chair- — "The Cape 

 Town Main Drainage Scheme": H- S- Perkins- An account of 

 the inception of the scheme and the carrying out of the works- The 

 total cost of the scheme was about £274,000, and the average annual 

 cost of maintenance, including the working expenses of the low-level 

 areas, was about £2,000- 



ADDRESSES WANTED- 



The Assistant General Secretary (P-O- Box 1497. Cape Tovn) 

 would be glad to receive the correct addresses of the following members,- 

 whose last-known addresses are given below: — 



Aspland, C- Hatton, Witwatersrand Deep, Ltd-, P-O- Box 5, Knight's, 



Transvaal- 

 P.arton, Ernest Mortlock. Director of Works Department, Simons- 

 town. Cape- 

 U<\\. Dr. B-, P-O- Box 55 H- Johannesburg- 

 Beil, W- Reid, M-I-C-E-, E-R- Met- Soc-, M-l-E-S-, P.O, Box 2263,. 



Johannesburg- 

 Roulton, H- C-, c/o Messrs- Pauling & Co-, Ltd-, Broken Hill,. 



Rhodesia- 

 Brown, W- B-, c/o Enginecr-in-Chief, S-A- Railways, Cape Town- 

 Champion, Ivor Edward. P-O- Roberts Heights, Pretoria- 

 Crockett, John, 10, Transvaal Bank Buildings, Johannesburg. 

 Dickie. Andrew, 475, Currie Road. Durban. Natal- 

 Leech, Dr- J- R-, 4th Avenue, Melville, Johannesburg. 

 Macfarlane, Donald, M-1-C-E-, H-M- Naval Dockyard, Simonstowur 



Cape- 

 Mirrilces, vV- J-, 9, London Chambers, Durban- 

 Xichol. Thomas Thompson, P-O- Box 34, Springs, Transvaal- 

 Nicholas, W- H-, Durban High School. Durban, Natal- 

 Nicholson, J- Greg, Leliefontein, Government School, P-O- Carolina, 



Transvaal- 

 Petersen, H. T-, P-O- Box 5, Cleveland, Transvaal- 

 Preston, James, 89, Arnold Road, Observatory, near Cape Town- 

 Southwell, Miss Jessie, 270, Visagie Street, Pretoria- 

 Van Oordt, J. E., Harrismith, O-F-S- 



