Evening Republican, Volume 15, Number 286, Rensselaer, Jasper County, 5 December 1911 — A SIMFLE MEDICAL COIL. [ARTICLE+ILLUSTRATION]

A SIMFLE MEDICAL COIL.

a skilled mechanic to undertake. This » « ariial mietaVa hn*avn» aa It U make a coil that will give goodT re suits at a cost of but a few cents, and with the use of only the moot ordinary For the core there may be used an iron bolt about three inches long and three-eighths of an inch in diameter, as shown at A to the accompanying drawing. It is a good plan to soften the bolt by heating it red hot in a lire and allowing it to cool slowly. Make two thin wooden washers about an inch and a quarter tn diameter, and glue them on to the bolt to form a spool as shown at B, and sover the iron between the heads with a wrapping of two layers of paper glued on. The nut shown is not necessary, but makes a neat finish. The first part of the winding, or primary coil, requires about half an ounce of No. 20 or No. 22 double cot-ton-covered magnet wire. Pass the end of the wire through a small hole in one of the heads, and wind on a smooth layer of the wire like thread on a spool When the opposite bead is reached wind a sec ond layer .of wire over the first one back to the place of beginning. Cui a second hole tn the head near the first one. as shown at D. The excess of wire will be useful for connections The next part of the winding, or secondary coll, requires an ounce ni two of No. 32 single cotton, covered magnet wire. Finer wire gives more powerful results because of the greater number of turns tor a given weight, but it is rather delicate to handle. Be fore winding on any of this wire, glue on a wrapping of two or three layers of paper over the primary coll, to keep

the two coila entirely separate. The secondary wire need not be wound in layers, though care is required to avoid injuring the insulation or breaking the wire by pulling it too tight The two ends may be left projecting. ,as shown at H, for connection to two handles or electrodes, and the coil may be protected by a final wrap ping of paper, as shown at,<3. One pole of a dry battery E is connected to the tang 6f a large file F. and' the other to pne of the primary terminals D. The remaining primary terminal G is then lightly dragged along the surface of the file, thus making and breaking the circuit in rapid succession as the wire passes over the teeth. If the shocks received from the handles are too strong, use a longer piece of wire at G; if too weak, add another Any battery in series, or put more wire on the secondary.

A Simple Medical Coil.