The Science Society

MUSIC

BEFORE THE PLAY Overture, "Egmont" Beethoven DURING THE INTERVAL "Water Music" Handel AFTER THE NATIONAL ANTHEM "Noel" Balfour Gardiner The Players: R. ATKINSON (Violin) W. B. HAWKINS (Viola)

J. FORD (Flute) R. D. WELCH (Clarinet)

A. BLOOMFIELD (Piano)

President: MR. E. K. ROBINSON. Secretary: J. FORD. Treasurer: D. A. STABLER. House Representatives:

Grove: Rise:

STABLER, D. A.; CARR, N. W. M. IBBERSON, W. R.; HUZZARD, J. B. Manor: Queen's:

ELSTON, C. S.; SAVILLE, J. M. STAINES, A. G. D.; VYLE, C. J. School House: Temple:

MCCALLUM, M. J.; RIDLEY, G. BARTON, D. G.; NETHERWOOD, P. J.

At the first meeting of the new school year a lecture entitled "A Forestry Tour" was given by Mr. C. A. Connell, M.A. The tour consisted of an account of his experiences whilst attending an international forestry mission in the United States, the main purpose of which was to deal with fire prevention and suppression.

The starting point was the thickly wooded shore of Lake Priest, and after explaining how rafts were made to transport the timber to the saw-mills, Mr. Connell moved on to the State of Ohio.

Mr. Connell explained that fires in this district were usually due to lightning striking "snag" trees, the name given to previously burnt trees. The insides of these might burn as long as two or three days before falling amongst other trees, thus igniting them.

The fire-fighting system for such a vastly wooded area, in all onethird of the United States, has to be extremely efficient, and the lecturer finished by explaining the many ways in which a fire was dealt with. "Stainless Steel" was the title of the second lecture of the term given by Mr. McWilliam. He began by showing two charts which gave the distribution of various substances in steel used to produce differing characteristics. Chromium, for instance, is employed extensively for hardening purposes, and the addition of small percentages of sulphur and molybdenum gives a steel which is suitable for work at high temperatures.

The lecturer mentioned two main ways of welding, the first being the argon arc, in which the argon forms an envelope round the arc when struck, and hence prevents oxidation of the steel. The second method, known as the electric resistance spot-weld, makes use of two hard copper pointed electrodes, operated by a current of the standard 50 cycle frequency. The difference between the two is that the first is a continuous weld, whilst the second is in a stitched form.

Mr. McWilliam illustrated this part of his lecture with slides, the last few of which showed some applications of the steels mentioned, and in conclusion a film entitled "Stainless Steel in Power Production" was shown.

Mr. P. L. Harris gave the third lecture of the term on an up-todate topic, "Rocket Propulsion". He began by explaining how the propulsive force might be likened to the recoil of a gun, and pointed out that the ratio of the mass of fuel to that of the rocket was an extremely important factor to be taken into consideration. For instance by jettisoning fuel tanks it would be possible to effect an increase of 1 :4 to 1 :226.

The lecturer then went on to consider the chemical aspects of a rocket. Both liquid and solid fuels have been used, the disadvantage of a liquid being that it has to be fed to the combustion chamber, but this is not necessary for a solid.

The most depressing aspect of rocket propulsion undoubtedly lies in its use as a military weapon. It is relatively cheap, and the accuracy it possesses over a hundred miles is a circle of radius 10 feet.

Mr. Harris went on to explain the essentials of interplanetory travel, and described the details and requirements for a sixteen-day voyage to the moon. He concluded by saying that such a journey would be quite within the realms of possibility in 10 to 20 years' time.

The penultimate meeting was devoted to a lecture on the theory and principles involved in the polarising microscope, and was given by Mr. Hall.

As an introduction he described an older type of instrument used for the measurement of crystals, known as a goniometer, before going on to describe the polarising microscope itself. The first essential for this microscope is a continuous source of light, that is, one which will give the complete spectrum, if it is to provide a true representation of colour. The microscope employs two pieces of polaroid, one below the condenser, called the polariser, and the other in the microscope tube, known as the analyser.

After describing the optical requirements the lecturer gave a simple treatment of some of the wave theories of light, before going on to explain the phenomenon of optical indicatrix, that is, changing 31