552 THE MEDICINAL SPRINGS OF SOUTH AFRICA. 



complete, I feel that there must still he a considerahle amount 

 of infcrmation which I have not succeeded in collecting. I am 

 particularly indebted to Dr. A. W. Rogers and Dr. A. L. du 

 Toit. of the Geological Survey, for furnishing me with geologi- 

 cal notes about the springs in the Cape Province ; to Air. A. L. 

 Hall, cf the Geological Survey, Pretoria, for a list and descrip- 

 tion of the majority of the Transvaal springs; to Mr. H. B. 

 Maufe, Director of the Geological Survey. Bulawayo. for sup- 

 plying me with information about the Rhodesian springs ; and 

 to Dr. C. F. Juritz, of Capetown . and Dr. McCrae, of Johannes- 

 burg, for placing many of the analytical data at my disposal. I 

 also received valuable assistance from: Prof. P. D. Hahn, Dr. 

 W. Versfeld, Dr. W. Darley-Hartley, Capt. Dunley-Owen. M.D.. 

 Professor A. Young, of Capetown; Rev. Mr. Smit, Muizenberg; 

 Dr. A. L. de Jager, M.L.A., Paarl ; Mr. I. Meiring, Worcester; 

 Dr. Bensley, Beaufort West ; the Caledon Baths Ltd. ; Dr. Bau- 

 mann, Mr. Frood, Capt. Heywobd, Bloemfontein ; Miss Wilman, 

 j. W. Ross, Librarian, Public Library, Kimberley ; the New 

 Transvaal Chemical Company, Delmore ; Dr. Wagner, Lieut. - 

 Col. J. (t. Rose; Dr. H. Brauns, Willowmore ; Dr. Querney, Port 

 St. John's; Mr. F. Dawson, General Manager of the New Cape 

 Central Railway, Ltd. ; Mr. H. F. Walker. Senr.. Choma. North 

 Rhodesia; Mr.' T. N. H. Janson, Dullstroom ; Dr. J. W. Mat- 

 thews, Lilani ; Mr. FI. A. van Schalkwyk. Standerton ; Mr. O. F. 

 Brotherton, African Farms, Ltd., Johannesburg; Mr. H. Ma- 

 gennis, Balmoral, Uitenhage ; Mr. F. Alullcr Rex, Oudtshoorn ; 

 Mr. J. Laing, Algoa Mining Comj^any, Ltd.. Port Elizabeth; Mr. 

 A. Coster, Mr. G. Baumann, Bloemfontein ; Dr. Macrae, Cloco- 

 lan ; Mr. J. Home, Parys ; Mr. Chas. McCuUoch, Lindley ; Pro- 

 vincial Secretary, Pretoria; Mr. A. C. Mitchell, Jagersfontein ; 

 the Van Riebeek Natural Mineral \A' ater Co., Ltd., Capetown ; 

 the United Mineral Water Co., Pretoria ; Rev. Mr. Blazey, 

 Dys.selsd'jrp ; the Secretary of the Transvaal Medical Council; 

 The Medical Journal of South Afriea; the Secretary, Cok)nial 

 ^ledical Council; .Mr. .\. F. \. Zealley and Mr. G. Arnot.t, 

 Curator, Rhodesia Alu.seum. Bulawayo; the ALigistrate, Piet 

 Reticf ; and the Mayors and Town Clerks of Aliwal North, 

 Bloemfontein, Clanwilliam. Colesberg, Graafif-Reinet, Machado- 

 dorp, .Malmesbury, Willowmore, Worcester, Citenhage and 

 \'r\h('id. 



Transmission of Sound Waves.— Dr. C. Davison, 



in the course of an article in Nature* says that tlie most remark- 

 able result of recent investigations, with regard to the transmis- 

 sion of sound waves by the atmosphere, is the recognition of the 

 fact thai there is sometimes a zone of silence separating two 

 detached sound areas. Ibis zone has been traced in 22 recent 

 e\i)losions. of which two were due to gun-lirin,y, four to explo- 

 sions of dynamite or gunpowder, and 16 to volcanic explosions. 



• 98 (1917), 438-9- 



