When the carrier wheels are on either side of the nozzle or just back of it, keeping the nozzle slightly above the carpet, the operator, if skilful, can do a good job. Second: Using air plus a brush: The brushes are used as follows:--(1) Straight bristle brush (looks like a comb of bristles) attached inside or outside of nozzle, projecting slightly below it so that it will comb the carpet. (2) Spirally wound bristle brush fitted inside the nozzle opening and operated by the carrier wheels, either with a belt or gears. This brush moves in the opposite direction to that in which the cleaner is pushed, and takes up the lint and hair, etc. AS TO MOTIVE POWER Motor driven brushes are driven by a belt attached to the motor. It is continually in action when the motor is running except, of course, when the brush is removed for any reason. The surface is continuously swept as the air passes through the nozzle, and there is, of course, more power in the motor driven brush. But its enemies in the friction brush camp aver strongly that the brush is prone by its velocity to wear the carpet! These brushes generally have two rows of spirally wound bristle, and in this type you get away from the old-time carpet sweeper where lint and threads adhere for a long time to the bristles and often return again to the carpet. Third: Using air with beating and sweeping. These sweepers have a large brush in a large nozzle and the brushes are spirally wound in two rows with a simple belt connection to the motor. These machines are generally adjusted so that the nozzle is about ¹⁄₄″ above the carpet. The bristles extend enough below the nozzle so that the bristles push away the carpet as the air draws it up. This gives the shaking motion at the same time the bristles, coming down at an angle on the carpet, beat it and passing through the nap comb and sweep it automatically. The bristles comb the nap and the air, passing through, cleans the carpet and the imbedded dirt is loosened by the shaking. The surface litter and hair is swept up and it cleans efficiently by applying all the laws of cleaning at the same time. Of course, with the cleaner come tools for altitude cleaning, for blowing out dust from books, moldings, upholstery tuftings, etc., etc. The extra tools are absolutely necessary and it is well to remember that the price is generally given you without the extra $7 to $10 being added. Tools are made of aluminum steel and fibre, which means that they are durable and will withstand much wear and tear.