There is still another item of information necessary to be supplied with an order for a motor, other than those of fractional horsepower. With motors of a horsepower or more it is necessary to state the number of phases included in the circuit. This information to be complete must state whether the motor is to operate on a single-phase, two-phase, or three-phase circuit. These terms apply to a condition made possible in A.C. generation that permits one, two, or three complete impulses to be developed in a circuit at the same time. These phases are transmitted by three wires, any two of which will form a circuit and give a supply of energy at the same voltage. Either one phase or all may be used at the same time and for this reason the phase of an A.C. motor should be given in an order. To make the information complete there should be included the number of cycles or complete electric impulses per second produced in the circuit. Suppose that a 1-horsepower motor is required to work on an A.C. circuit of 110 volts. Inquiry of the electric company reveals that the circuit is three-phase at 60 cycles per second. The dealer on receiving this information will be able to send a motor to suit your conditions. Most A.C. motors of 1 horsepower or less are of the single-phase variety. In the case of D.C. motors it is necessary only to state the voltage of the circuit to make the required information complete. =Fuse Plugs.=--Every electric circuit is liable to occurrences known as short-circuiting or “shorting.” This is a technical term describing a condition where, by accident or design, the wires of a circuit are in any way connected by a low-resistance conductor or by coming directly into contact with each other. In case of shorting, the resistance is practically all removed and the amount of current which flows through the circuit is so great as to produce a dangerous amount of heat in the wires. If the covering of a lamp cord becomes worn so as to permit the bare wire of the two strands to come together, a “short” is produced. Immediately, the reduced resistance permits the electric pressure to send an amount of current through the wires, greater than they are intended to carry. When this occurs an electric arc will form at the point of contact with the accompanying flash of vaporizing metal and the wire will finally burn off. Fires started from this cause are not uncommon.