(under subclass 229) Subject matter which includes a part next to one surface of the material and the apparatus to sense and indicate the sensing of the magnetic field next to the other surface opposite to the part; the part and the apparatus cooperating with each other to place tested material in the same relation each time with respect to the magnetic field and the apparatus to sense and indicate the sensing of the field.
(1) Note. The part generally but not always is part of the magnetic test circuit.
