over, warm artesian springs containing sulphide and sulphate, and lakes in sunny cli- 

 mates might be induced to produce sulphur. 



Present methods of harvesting the sulphur in the Cyrenaican lakes are very primi- 

 tive and give an impure product. The yield would be improved by better extraction 

 procedures, if it were economically feasible to use machinery in so remote an area. 

 The sulphur yield alone would probably not justify such an enterprise, but combined 

 with exploitation of the carnallite deposits at Marada, some 30 miles to the south, a 

 viable industry might be developed. 



Summary Summary 



The continuous deposition of sulphur in certain Cyrenaican lakes is attributed 

 mainly to the combined action of (1) sulphate- reducing bacteria, and (2) photosynthe- 

 tic sulphide - oxidising bacteria {Chlorobium and Chromatium). In laboratory experi- 

 ments, the latter synthesized organic matter for bacterial growth and sulphate reduc- 

 tion. 



Some natural sulphur deposits may have been laid down by a similar process. 

 Sulphur production might be stimulated or induced in other lakes. 



Acknowledgements 



The authors are indebted to Miss M.E. Adams and Mrs M. Long for technical assistance, 

 to the Government Chemist for analysis of the water sample and to Professor J.L.B. Smith, 

 (Rhodes University, South Africa) for identifying the fish from the lake as Cyprinodon. 



They gratefully acknowledge the help of officials of the British Administration in Cyre- 

 nalca in facilitating their journey to the lakes, the provision of transport by the Cyrenaican 

 Government and the loan of camping equipment by the Army. They also wish to record their 

 appreciation of the helpfulness and hospitality of the Arab assistants who accompanied them 

 on their journey. 



This paper is published by permission of the Director of the Chemical Research Laboratory. 



References 



Allen, M.B. 1952 Arch. Microbiol. 17, 34. 



Adams, M.E., Butlin, K.R., Hollands, S.J., & Postgate, J.R. 1951 Research. 4, 245. 



Chemistry Research 1930. 1951 H. M. Stationary Of/ice, 85. 



Desio, A. 1935 Missione Scient. R. Ace. d'ltalia a Cujra, 1, 369. 



Hunt, W.F. 1915 Econ. Geol. 10, 543. 



lya, K.K., & Sreenivasaya, M. 1944 Current Sci. 13, 316. 



Mancuso, V. 1939 Ann, Mus. LibioStor. Nat. 1, 307. 



Murzaev, P.M 1950 C. R. Acad Sci., U.R.S.S.. 72, 343- 



van Niel, C.B. 1931 Arch. Microbiol. 3, 1. 



Pinfold, E S. & Gee, E.R. 1949 Board of Trade Report. 



Schneegans, D. 1935 Congr. Intern. Mines, Met., geol. Appl. 1, 351 (quoted in Amer. Chem. Abs. 

 1937, 31, 2562) 



Senez, J. 1951 Vie et Milieu. 2, 5. 



Smith, J.L.B. 1952 Ann. Mag. Nat. Hist. (12). 5, 888. 



Subba Rao, M.S. 1951 Thesis for A.I.I.S., Indian Institute of Science, Bangalore. 



Subba Rao, M.S., lya, K.K., & Sreenivasaya, M. 1947 Proc. 4th InL Congr. Microbiology, 494. 



ZoBell, C.E. 1936 Marine Microbiology, 112. Mass: Chron. Bot. Co. 



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