Refrigerator, [100], [101], [102], [103], [104], [105]

Register, [60], [62], [75]

Regulation, heat and pressure, [20], [60], [66], [70], [72], [73]

Regulation of stoves, [24], [43], [44], [48]

Regulator, temperature, [198], [199]

Reservoir, [18]

Resistance produces heat, [143]

Revolutions of motor wheels, [137]

Ribbon, typewriter, [203], [208]

Roller, [138], [141], [142], [154], [162]