the present-day scientists. The greatest advance made in this field was the discovery of penicillin by Sir Alexander Fleming. R. L. Evans continued the lecture by considering a whole range of antibiotics, and their effectiveness against the various organisms responsible for disease. The result of this investigation showed that no antibiotic was entirely effective in its use against all disease organisms. T. Chilman, talking on Analysis, explained and demonstrated the means by which compounds under investigation may be analysed. The simplest means is by chemical precipitation. More complex analyses employ mass spectrography, chromatography, and spectroscopy. The lecturer considered the relative merits and demerits of each method. The second lecture was very brief, and concerned Harmonic motions, and Lissajou's Figures, which were demonstrated by experiment on the School harmonograph. For our fourth meeting we were visited by two officers from the School of Signals, Catterick Camp, who lectured on various aspects of wireless communication. Major Burrows explained the nature of radio waves, the characteristics of the three types of waves (which vary with their frequency) and the differing uses made of them. He showed a number of up-to-date sets and allowed members of the Society to operate them. He indicated that radio sets of the future would be smaller, lighter and more efficient and that transistors would be much more used. Major Mullaly explained how a wireless wave could be made to carry speech. The three ways of modulating a carrier wave were (a) amplitude modulation in which the amplitude of the carrier is made to vary in direct proportion to the speech wave, (b) frequency modulation, in which frequency was made to vary, and (c) speech analysis in which the speech was broken down into a number of parts, each part modulating a separate carrier. The Society is very grateful to those boys who have given lectures and demonstrations and to visitors to the School, who have included three lecturers from Leeds University. T.C.
THE JUNIOR SCIENCE SOCIETY At the first Society Committee Meeting of the year, the Society was split, to form the Junior and Senior sections; thus, after the first joint meeting, the two Societies went their separate ways. Three speakers from the Grove were invited for the first meeting, D. E. Rayner, R. M. Wheeler, and R. L. Evans; their talks were on, respectively, oil refining, tapered roller bearings, and penicillin. The second of these, Wheeler's talk, was rather above the heads of most members, although it interested all present. R. L. Evans made an offer for a small party to go on a tour of Glaxo Laboratories, but
29
