Improving field analogues by transformation

A CONDUCTION analogue such as the electrolytic tank is a familiar device for the solution of problems involving electric, magnetic, thermal, and other fields. The accuracy of measurements made in this way is often limited by distortion of the field produced by the boundaries of the conducting medium and by practical limitations on the size of the model. In 1949 Boothroyd, Cherry, and Makar¹ described an ingenious circular double tank which was used for the study of impedance functions and which essentially eliminated the usual errors caused by the tank walls. Their technique is actually a special case of a general method based on conformal mapping.