Abstract: Apparatus is disclosed for feeding an inoculating or nucleating agent or particle to a trough of a pipe casting apparatus or beneath the surface of molten metal within a ladle. In particular, the agents are introduced by a hopper into a sealed chamber by selectively actuatable valves. A gas compatible with the agent to be used in the casting process, is introduced into the sealed chamber, whereby a relatively low pressure is established therein. An agent feeder, such as a vibratory feeder, is provided for directing a measured charge of the agent into a funnel leading to an outlet conduit. The pressure established within the chamber forces the agent through the conduit which is in turn connected to a delivery tube by which the agent is used to coat the mold surface directly or is fed into a stream of metal in a centrifugal tube casting apparatus. An outlet valve in the outlet tube is provided for selectively permitting the passage of the agent and gas mixture to the casting apparatus.