Nor do modern improvements in baking appliances stop short at ovens. Most bakers doing a good business use kneading machines, of which there are many in the market. With one exception—that of the Adair mixer, which has no arms nor beaters, but simply rotates, and by this action the flour and water pass through the rods of iron, which are placed crosswise in the machine, and become perfectly and proportionately mixed—they are all, more or less, on the same principle, of revolving arms, blades, or knives by which the flour and water are properly mixed, and the position of the dough being perpetually changed, it is effectually kneaded without the objectionable intervention of manual labour. The earliest kneading machine that I can find mentioned is in 1850, when the illustrious philosopher, Arago, presented and recommended to the Institute of France the kneading and baking apparatus of M. Rolland, then a humble baker of the Twelfth Arrondissement. The kneading machine was described as exceedingly simple, and capable of being worked, when under a full charge, by a young man from 15 to 20 years old, the necessity for horse labour or steam power being thus obviated; and it was claimed that in less than twenty minutes a sack of flour could be converted into a perfect homogeneous and aërated dough altogether superior to any dough that could be obtained by manual kneading. Another attempted improvement in the manufacture of bread was aërating the dough without using any ferment, such as yeast, etc., and this has been accomplished by means of mixing hydrochloric acid and carbonate of soda with the dough, or using bicarbonate of ammonia, or forcing carbonic acid into the water with which the flour is mixed. The latter is called the Dauglish system, from its inventor, the late John Dauglish, M.D. (born 1824, died January 14, 1866), and it is now in full working operation. By this system carbonic acid gas is generated as if for making soda water, and, supposing a sack of flour was to be converted into dough, the following would be the treatment: A lid at the top of the mixer is opened, and the flour passed down into it through a spout from the floor above. The lid of the mixer is then fitted tightly on, and the air within it exhausted by the pump. The requisite quantity of water, about 17 gallons, is drawn into the water vessel, and carbonic acid is forced into it till the pressure amounts to from 15lb. to 25lb. per square inch. The aërated water is then passed into the mixer, and the mixing arms are set in motion, by which, in about seven minutes, the flour and water are incorporated into a perfectly uniform paste. At the lower end of the mixer a cavity is arranged, gauged to hold sufficient dough for a 2lb. loaf, and by a turn of a lever that quantity is dropped into a pan ready for at once depositing in the oven. The whole of the operations can be performed in less than half an hour.