A THIRD circular on the coming Fourth Empire Mining and Metallurgical Congress has recently been published. Details of this Congress have already been reported (see Nature, February 5, p. 206), but this new circular, besides covering all the points previously mentioned, contains the final programme details in the various centres, a list of papers to be read and a list of delegates. The general time-table is : July 9-12, inauguration of the Congress in London, and short excursions in the London area ; July 13-17, technical sessions in Oxford ; July 18-23, excursions to a choice of one of the four following centres–Cardiff, Cornwall, Edinburgh or Newcastle-on-Tyne. The sessions in Oxford will be organised as follows : A and B, mineral resources ; C modern methods of prospecting ; D, physiological and psychological effects of heat and humidity on workers in deep mines and metallurgical works ; E, petroleum ; F, coal ; G, present-day trends in mineral dressing ; H and I metallurgy and metallurgical industries. In addition to the technical papers which will be presented at these sessions, three evening lectures will be delivered : "Metallurgical and Mining Aspects of Atomic Energy" by Sir John Cockcroft, director of research (atomic energy), Ministry of Supply ; "Miners as Pioneers" by Dr. Charles Camsell, formerly Deputy Minister of Mines and Resources, Ottawa ; and "The General Theory .of Metals and Alloys" by Dr. W. Hume-Rothery, lecturer in metallurgical chemistry, University of Oxford. Besides the member States of the British Commonwealth, eleven other countries will be represented at the Congress, as follows : Belgium, Chile. Egypt, Holland, Iraq, Italy, Norway, Spain, Sweden, Switzerland and the United States. Further information may be obtained from the Joint General Secretaries, Fourth Empire Mining and Metallurgical Congress, 436 Salisbury House, Finsbury Circus, London, E.C.2.