may be increased, and the gas passed from one to the other until the gas is perfectly clean. This series of operations would, however, with any kind of washer, result in thoroughly cleansing the gas. The only thing that makes such a process practically impossible is the very considerable or it may be even total loss of pressure which it entails. By the new system, the loss of pressure is _nil_, inasmuch as each turbine becomes in reality an exhauster. The gas, entering the washer at the axis, is drawn to the circumference by the rotatory motion of the brooms, which thus form a ventilator. It follows, therefore, that on leaving the vessel the gas will have a greater pressure than it had on entering it; and this increase of pressure may be augmented to any desired extent by altering the speed of rotation of the axis, precisely as in the case of an exhauster. Forcing the gas violently into water, and at the same time dividing the current, is evidently the most simple, rational, and efficient method of washing, especially when this operation is effected by brooms fixed on a shaft and rotated with great speed. Therefore, if there had not been this loss of pressure to deal with--a fatal consequence of every violent operation--the question of perfect washing would probably have been solved long ago. The invention which I have now submitted consists of an arrangement which enables all loss of pressure to be avoided, inasmuch as it furnishes the apparatus with the greatest number of valuable qualities, whether regarded from the point of view of washing or that of condensation. [Illustration: Longitudinal Section. Elevation. Transverse Section.]