In his opening remarks, Mr. Young stated that the magneto was an electrical machine of very small compass for converting mechanical energy into electrical energy at a very high potential. The electrical energy appears as high tension sparks which occur at regular intervals and in synchronism with the movement of the pistons. Each spark is the result of a very rapid rise of pressure in the secondary winding of the armature of the magneto. To-day magnetos are being produced capable of giving regularly 16,000 sparks per minute or 270 sparks per second.