A heavy Stainless steel tube (S.W.G. No. 16) 1.10 mm in length x 25 mm dia. is mounted next to a meter scale. The Stainless Steel pipe and meter scale is fitted on a superior quality polished wooden board. The lower end of the Stainless Steel pipe is sealed into a metal cup having a side tube connected by rubber tubing to a brass reservoir, also mounted on the support rod but with elevation adjustment. The length of the resonance column may easily be determined by measuring the distance between zero stop and the closed end of the tube with the meter rule. Supplied without rubber tube.