We offer Apparatus for Measurement of Susceptibility of Paramagnetic Solids by Gouy’s Method in this, the solid sample in the form of a long cylinder (area of cross section A) is hung from the pan of a balance and is placed such that one end of the sample is between the pole-pieces of the magnet  (field H ) and the other one is outside the field. The force exerted on the sample by the inhomogeneous magnetic field is obtained by measuring the apparent change (Δm ) in the mass of the sample. The susceptibility χ is given by
 

                 χ = 2Δmg/AH²
 

If the sample is in the form of powder, it is filled in a long nonmagnetic tube which is then suspended from the pan of the balance.

The set up consists of the following:
(a) Digital Balance, Capacity: 200gms   Sensitivity: 1/10 mg. by vernier  

Or Beam Balance Beam: Hard Bronze/ Brass
Circular, falling away type   Air Damping: Very quick and positive, beam coming to rest in 2-3 sec

(b) Sample in the form of a long rod:        Set of 4 samples, 2 each of Ebonite and Wood

(c) Electromagnet,                                                     Pole Pieces: 75mm tappered to 25mm
     Mag. Field: 20KG at 6mm airgap                           Energising Coils: Two of approx. 13Ω each
     Power: 0-90Vdc, 3A, for coils in series                  0-45Vdc, 6A, for coils in parallel

(d) Constant Current Power Supply,
Current: 0-3A per coil Smoothly adjustable                           Line Regulation: ±0.1% for 10% mains variation
Load Regulation: ±0.1% for load variation from 0 to max     Display: 3½ digit, 7 segment LED display
Protection: Protected against overload, short circuit and transients caused by the load inductance.
Power: 220V 10%, 50Hz
   
(e) Gaussmeter,  Digital
The experiment is complete in all respect.