Marker for Defective Hydrants Metal discs for indicating the presence of defective hydrants have been designed by Deputy Chief John J. McCarthy of the New York Fire Department. Chief McCarthy believes that the use of these discs as a marker around the hydrant outlet will prevent delay in getting water to a fire as the device represents a cheap, efficient way of denoting the presence of defective hydrants to members of the department. These discs were described in full on page 443 of the December, 1934, issue of FIRE ENGINEERING. The department has issued General Order No. 51 regarding their use.