may be boiled in an emulsifying solution of grinding or cutting compounds diluted with water. In such cases, the bearings must be thoroughly drained and spun until all moisture has evaporated, then immediately washed in clean petroleum solvent or kerosene by revolving them slowly by hand and gradually working up to spinning speed. Care should be taken that all solid particles are removed, by a brush if necessary, before turning or spinning the bearing. After the bearings have been thor- oughly cleaned, spin them in clean, new light oil until the solvent has been completely removed. Relubricate the bearings immediately after they have been cleaned and washed. If they are to be stored before remounting, coat them with clean high grade oil or petrolatum and wrap in clean, oil-proof paper. Petroleum solvents are inflammable and must be used with caution because of the fire hazard involved. Carbon tetrachloride or similar solvents are sometimes used because they are non-inflammable, but their use is discouraged in cleaning bearings because they leave the bearing surfaces bone dry and subject to rust. Compressed air is sometimes used to blow out bearings, but it is not recommended unless the air is free from dirt and moisture. | If used, the bearing must be held so as to prevent spinning which may cause scoring of the bearing surfaces by dirt. The ball bearings of horizontal machines only may, if desired, be cleaned without disassembling the motor by the following method: Remove the filler and drain plugs and free the holes of any hardened grease. Flush a light oil heated to about 190°F through the housing while slowly rotating the shaft. Repeat until the oil comes out clean indicating that most of the old grease has been removed. In cases where the grease 3-33