A linear or linear-resistance type of flowmeter can consist of a straight piece of pipe with a porous plug, or a resistance element and a differential gage across the porous plug. In a certain flow range the volume rate of flow through the meter is directly proportional to the pressure drop across the plug. An investigation was made of linear flowmeters with copper-wool and brass-screen disk elements; the fluid was water. The tests cover a range of plug lengths and plug specific weights. A set of dimensionless ratios is proposed for a correlation of all the data for general application.