CHAPTER XXVIII.

WIRE TABLES.

_Copper Wire Tables_ are very convenient, and a necessity when working electrical examples. The tables here given are taken from a dealer's catalogue, and will be found sufficiently accurate for ordinary work.

_Explanation of Tables._ In the _first_ column are given the sizes of wires by numbers. The B & S or American gauge is used. In the table below is given a comparison between the B & S and the Birmingham gauges.

The _second column_ gives the diameters of wires. The diameter of No. 36 wire is 5 thousandths of an inch; the diameter of No. 24 wire is a little over 20 thousandths or 2 hundredths of an inch.

The _third column_ contains what is called circular mils, a mil being a thousandth of an inch. The figures in this column are obtained by squaring those in the second; thus, for No. 36 wire, 5 × 5 = 25. This column is useful when working examples where the squares of the diameters are wanted. The rest of the table explains itself.

The table at the bottom gives a comparison between the fractional and decimal parts of an inch. Space can not be given here for a series of examples showing the many uses of this table. (See "Elementary Electrical Examples.")

COPPER WIRE TABLES.

(Based on the B. A. Unit.)

=====+=======+=========+=======+===================================+ Gauge| DIAM- |Sectional|Capac- | OHMS | | ETER. | AREA | ity. | | -----+-------+---------+-------+-----------+----------+------------+ B.&S.| In | In |In Amp-| Per | Per | Per | No. |1000ths|Circular | eres. | 1,000 | Mile. | Pound. | | | Mils. | | feet. | | | -----+-------+---------+-------+-----------+----------+------------+ 0000|.460 |211600. | 312. | .04906| .25903| .000077| 000|.40964 |167805. | 262. | .06186| .32664| .00012 | 00|.3648 |133079. | 220. | .07801| .41187| .00019 | 0|.32486 |105534. | 185. | .09831| .51909| .00031 | 1|.2893 | 83694. | 156. | .12404| .65490| .00049 | 2|.25763 | 66373. | 131. | .15640| .8258 | .00078 | 3|.22942 | 52634. | 110. | .19723| 1.0414 | .00125 | 4|.20431 | 41743. | 92.3 | .24869| 1.313 | .00198 | 5|.18194 | 33102. | 77.6 | .31361| 1.655 | .00314 | 6|.16202 | 26251. | 65.2 | .39546| 2.088 | .00499 | 7|.14428 | 20817. | 54.8 | .49871| 2.633 | .00792 | 8|.12849 | 16510. | 46.1 | .6529 | 3.3 | .0125 | 9|.11443 | 13094. | 38.7 | .7892 | 4.1 | .0197 | 10|.10189 | 10382. | 32.5 | .8441 | 4.4 | .0270 | 11|.090742| 8234. | 27.3 | 1.254 | 6.4 | .0501 | 12|.080808| 6530. | 23. | 1.580 | 8.3 | .079 | 13|.071961| 5178. | 19.3 | 1.995 | 10.4 | .127 | 14|.064084| 4107. | 16.2 | 2.504 | 13.2 | .200 | 15|.057068| 3257. | 13.6 | 3.172 | 16.7 | .320 | 16|.05082 | 2583. | 11.5 | 4.001 | 23. | .512 | 17|.045257| 2048. | 9.6 | 5.04 | 26. | .811 | 18|.040303| 1624. | 8.1 | 6.36 | 33. | 1.29 | 19|.03589 | 1288. | .... | 8.25 | 43. | 2.11 | 20|.031961| 1021. | .... | 10.12 | 53. | 3.27 | 21|.028462| 810. | .... | 12.76 | 68. | 5.20 | 22|.025347| 642. | .... | 16.25 | 85. | 8.35 | 23|.022571| 509. | .... | 20.30 | 108. | 13.3 | 24|.0201 | 404. | .... | 25.60 | 135. | 20.9 | 25|.0179 | 320. | .... | 32.2 | 170. | 33.2 | 26|.01594 | 254. | .... | 40.7 | 214. | 52.9 | 27|.014195| 201. | .... | 51.3 | 270. | 84.2 | 28|.012641| 159.8 | .... | 64.8 | 343. | 134. | 29|.011257| 126.7 | .... | 81.6 | 482. | 213. | 30|.010025| 100.5 | .... | 103. | 538. | 338. | 31|.008928| 79.7 | .... | 130. | 685. | 539. | 32|.00795 | 63. | .... | 164. | 865. | 856. | 33|.00708 | 50.1 | .... | 206. |1033. | 1357. | 34|.006304| 39.74| .... | 260. |1389. | 2166. | 35|.005614| 31.5 | .... | 328. |1820. | 3521. | 36|.005 | 25. | .... | 414. |2200. | 5469. | 37|.004453| 19.8 | .... | 523. |2765. | 8742. | 38|.003965| 15.72| .... | 660. |3486. |13772. | 39|.003531| 12.47| .... | 832. |4395. |21896. | 40|.003144| 9.88| .... | 1049 |5542. |34823. | -----+-------+---------+-------+-----------+----------+------------+

=====+=======================+======================== Gauge| FEET. | POUNDS. | | -----+-----------+-----------+-----------+------------ B.&S.| Per | Per | Per | Per No. | Pound. | Ohm. |1,000 feet.| Ohm. -----+-----------+-----------+-----------+------------ 0000| 1.56122|20497.7 | 640.51 |12987. 000| 1.9687 |16255.27 | 507.95 | 8333. 00| 2.4824 |12891.37 | 402.83 | 5263. 0| 3.1303 |10223.08 | 319.45 | 3225. 1| 3.94714| 8107.49 | 253.34 | 2041. 2| 4.97722| 6429.58 | 200.91 | 1282. 3| 6.2765 | 5098.61 | 159.32 | 800. 4| 7.9141 | 4043.6 | 126.35 | 505. 5| 9.97983| 3206.61 | 100.20 | 318. 6| 12.5847 | 2542.89 | 79.462 | 200. 7| 15.8696 | 2015.51 | 63.013 | 126. 8| 20.0097 | 1599.3 | 49.976 | 80. 9| 25.229 | 1268.44 | 39.636 | 50. 10| 31.8212 | 1055.66 | 31.426 | 37. 11| 40.1202 | 797.649 | 24.924 | 20. 12| 50.5906 | 632.555 | 19.766 | 12.65 13| 63.7948 | 501.63 | 15.674 | 7.87 14| 80.4415 | 397.822 | 12.435 | 5.00 15| 101.4365 | 315.482 | 9.859 | 3.12 16| 127.12 | 250.184 | 7.819 | 1.95 17| 161.29 | 198.409 | 6.199 | 1.23 18| 203.374 | 157.35 | 4.916 | .775 19| 256.468 | 124.777 | 3.899 | .473 20| 323.399 | 98.9533 | 3.094 | .305 21| 407.815 | 78.473 | 2.452 | .192 22| 514.193 | 62.236 | 1.945 | .119 23| 648.452 | 49.3504 | 1.542 | .075 24| 817.688 | 39.1365 | 1.223 | .047 25| 1031.038 | 31.0381 | .9699 | .030 26| 1300.180 | 24.6131 | .7692 | .0187 27| 1639.49 | 19.5191 | .6099 | .0118 28| 2067.364 | 15.4793 | .4837 | .0074 29| 2606.959 | 12.2854 | .3835 | .0047 30| 3287.084 | 9.7355 | .3002 | .0029 31| 4414.49 | 7.72143| .2413 | .0018 32| 5226.915 | 6.12243| .1913 | .0011 33| 6590.41 | 4.85575| .1517 | .00076 34| 8312.8 | 3.84966| .1204 | .00046 35|10481.77 | 3.05305| .0956 | .00028 36|13214.16 | 2.4217 | .0757 | .00018 37|16659.97 | 1.92086| .06003| .00011 38|21013.25 | 1.52292| .04758| .00007 39|26496.237 | 1.20777| .03755| .00004 40|33420.63 | 0.97984| .02992| .000029 -----+-----------+-----------+-----------+------------

Comparative Table of the Fractional and Decimal Parts of an Inch.

+-----------------+ | 1/64 = .015625 | | 1/32 = .031250 | | 3/64 = .046875 | | 1/16 = .062500 | | 5/64 = .078125 | | 3/32 = .093750 | | 7/64 = .109375 | | 1/8 = .125000 | | 9/64 = .140625 | | 5/32 = .156250 | | 11/64 = .171875 | | 3/16 = .187500 | | 13/64 = .203125 | | 7/32 = .218750 | | 15/64 = .234375 | | 1/4 = .250000 | | 17/64 = .265625 | | 9/32 = .281250 | | 19/64 = .296875 | | 5/16 = .312500 | | 21/64 = .328125 | | 11/32 = .343750 | | 23/64 = .359375 | | 3/8 = .375000 | | 25/64 = .390625 | | 13/32 = .406250 | | 27/64 = .421875 | | 7/16 = .437500 | | 29/64 = .453125 | | 15/32 = .468750 | | 31/64 = .484375 | | 1/2 = .500000 | +-----------------+

Comparative Table of B. and S. and B. W. Gauges in Decimal Parts of an Inch.

+------------+--------------+-------------+ |Birmingham | American | No. of | |Wire Gauge. | (B. and S.) | Wire Gauge. | | | Wire Gauge. | | +------------+--------------+-------------+ | 0000 | .46 | .454 | | 000 | .40964 | .425 | | 00 | .3648 | .38 | | 0 | .32486 | .34 | | 1 | .2893 | .3 | | 2 | .25763 | .284 | | 3 | .22942 | .259 | | 4 | .20431 | .238 | | 5 | .18194 | .22 | | 6 | .16202 | .203 | | 7 | .14428 | .18 | | 8 | .12849 | .165 | | 9 | .11443 | .148 | | 10 | .10189 | .134 | | 11 | .090742 | .12 | | 12 | .080808 | .109 | | 13 | .071961 | .095 | | 14 | .064084 | .083 | | 15 | .057068 | .072 | | 16 | .05082 | .065 | | 17 | .045257 | .058 | | 18 | .040303 | .049 | | 19 | .03589 | .042 | | 20 | .031961 | .035 | | 21 | .028468 | .032 | | 22 | .025347 | .028 | | 23 | .022571 | .025 | | 24 | .0201 | .022 | | 25 | .0179 | .02 | | 26 | .01594 | .018 | | 27 | .014195 | .016 | | 28 | .012641 | .014 | | 29 | .011257 | .013 | | 30 | .010025 | .012 | | 31 | .008928 | .01 | | 32 | .00795 | .009 | | 33 | .00708 | .008 | | 34 | .006304 | .007 | | 35 | .005614 | .005 | | 36 | .005 | .004 | | 37 | .004453 | | | 38 | .003965 | | | 39 | .003531 | | | 40 | .003114 | | +------------+--------------+-------------+

LIST OF APPARATUS

FOR

The Study of Elementary Electricity and Magnetism by Experiment.

The =100= pieces of apparatus in the following list are referred to, by number, in the experiments contained in "The Study of Elementary Electricity and Magnetism by Experiment." This list is furnished to give those who wish to make their own apparatus an idea of the approximate size, etc., of the various articles used. The author is preparing a price catalogue of the articles included in this list, and of odds and ends needed in the construction of simple, home-made apparatus.

=No. 1.= A package of 25 steel sewing-needles. To be suitable for experiments in magnetism, these should be of good, hard steel, and not too thick.

=No. 2.= A flat cork, about 1 in. in diameter and 3/8 in. thick.

=No. 3.= A candle for annealing steel.

=No. 4-15.= One dozen assorted annealed iron wires, from 1 in. to 6 in. in length. The iron should be very soft.

=No. 16.= One English horseshoe magnet, 2-1/2 in. long, best quality.

=No. 17.= A small box of iron filings from soft iron.

=No. 18.= A compass (Fig. 5). The needle swings very freely; it is enclosed in a wooden pill box, the cover of which forms the support.

=No. 19, 20.= Two soft steel wire nails, 2 in. long.

=No. 21, 22.= Two pieces of spring steel, about 3 in. long and 3/8 in. wide, to be magnetized by the student and used as bar magnets.

=No. 23.= An iron ring, or washer, about 7/8 in. in diameter.

=No. 24.= A sifter for iron filings. This consists of a pasteboard pill box: Prick holes through the bottom with a pin.

=No. 25.= A thin, flexible piece of spring steel, about 3 in. long and 1/8 in. wide.

=No. 26, 27.= Two ebonite sheets (E S, Fig. 34), each 4 in. square. These are made with a special surface. They are very much better than the ordinary smooth ebonite.

=No. 28.= One ebonite rod (E R, Fig. 34), 3-1/2 in. long, with special surface.

=No. 29.= One ebonite rod, 1-3/4 in. long, with special surface, used to support the insulating table, No. 43 (I T, Fig. 32).

=No. 30.= One piece of flannel cloth, 7 in. square.

=No. 31.= Six sheets of tissue-paper, each 4 in. square.

=No. 32.= A few feet of white cotton thread.

=No. 33.= A few feet of black silk thread.

=No. 34.= One support base (S B, Fig. 56). This is of thin wood, about 3-3/4 in. by 6-1/2 in., to one end of which is fastened a spool for holding the support rod (No. 35).

=No. 35.= One support rod (S R, Fig. 56), 7 in. long and 5/16 in. in diameter. This rod has a hole in each end. The small hole is for holding the support wire (No. 36); the large hole is for the ebonite rod (No. 29).

=No. 36.= One support wire (S W, Fig. 144).

=No. 37.= One wire swing (W S, Fig. 29).

=No. 38.= One sheet of glass, 4 in. square.

=No. 39.= One bent hairpin (H P, Fig. 32).

=No. 40.= Bottom of flat box (B F B, Fig. 32), 3-5/8 in. in diameter.

=No. 41.= Top of flat box (T F B, Fig. 33).

=No. 42.= One electrophorus cover (E C, Fig. 34), 3-5/8 in. in diameter. This has rounded edges, and a small tube is riveted into the top of it to hold the insulating handle, E R.

=No. 43.= One insulating table (I T, Fig. 32). This is made the same as No. 42, and is supported by No. 29.

=No. 44.= One insulated copper wire, 2-1/2 feet long.

=No. 45.= One rubber band (R B, Fig. 33).

=No. 46.= Six bent wire clamps (B C, Fig. 37).

=No. 47.= One tin box conductor (T B, Fig. 42). This cylindrical conductor is about the size of an ordinary baking powder box.

=No. 48.= One hairpin discharger for the condenser.

=No. 49.= Two sheets of aluminum-leaf for the leaf electroscope (Fig. 57) and other experiments.

=No. 50.= One bent wire (H P, Fig. 57) used in connection with the leaf electroscope.

=No. 51.= A dry cell, ordinary size about 7 in. high and 2-1/2 in. in diameter.

=No. 52.= Enough mercury to amalgamate battery zincs. A wooden pill box containing about half a thimbleful will do.

=No. 53.= A coil containing 25 feet of No. 24 insulated copper wire for connections.

=No. 54.= One dozen spring connectors (Fig. 61) for making connections. These are made of brass, nickel plated, and do not affect the compass-needle.

=No. 55.= A telegraph key (Fig. 68) without switch. The metal straps are made of aluminum; they are 1/2 in. wide, and are fastened to a neat wooden base.

=No. 56.= Three metal plates, each about 2 in. by 3/4 in., on which spring connectors (No. 54) are to be pushed in order to join two wires.

=No. 57.= A current reverser (Fig. 69). The straps are made of aluminum and are fastened to a neat wooden base.

=No. 58.= A galvanoscope (Fig. 72) including a degree-card (No. 99). The cardboard coil-support, C S, is 5 × 6-1/4 in., and the hole in it is 3-3/8 in. in diameter. The coil is 4-1/4 in. in diameter, made of No. 24 insulated copper wire.

=No. 59.= An astatic galvanoscope (Fig. 77). The whole may be taken apart and mailed in the containing box, B, which is 4-3/8 × 3-1/8 × 1 in. The coil is made of No. 31 wire, and has a resistance of about 5 ohms. Spring connectors are used to join a wire to the apparatus by pushing the connectors into the tubular binding-posts, L and R.

=No. 60-63.= Four strips of sheet zinc, 4 in. by 1/2 in., not amalgamated.

=No. 64.= A carbon rod, 4 in. long (Fig. 81).

=No. 65, 66.= Two glass tumblers (Fig. 81).

=No. 67, 68.= Two strips of sheet copper, 4 in. by 1/2 in. (Fig. 85).

=No. 69.= One galvanized iron nail.

=No. 70, 71.= Two wooden cross-pieces (Fig. 85).

=No. 72.= One dozen brass screws, 5/8 in. long, size No. 5, with round heads.

=No. 73.= A porous cup (P C, Fig. 87) that will stand inside of the tumblers (No. 65).

=No. 74.= A zinc rod, about 3/8 in. in diameter, like those used in Leclanché cells.

=No. 75.= A sheet copper plate for the two-fluid cell (C, Fig. 87). This is 2 in. wide; it nearly surrounds the porous cup, and is supported upon the edge of the tumbler by a narrow strip, A, with which connections are made by spring connectors (No. 54).

=No. 76.= One strip of sheet iron, 4 in. by 1/2 in.

=No. 77, 78.= Two strips of sheet lead, 4 in. by 1/2 in.

=No. 79.= A resistance coil (Fig. 94). The coil is made of No. 24 insulated copper wire; it has a resistance of 2 ohms (nearly) and is fastened to a cardboard base. It is so arranged that either one or two ohms can be used at will.

=No. 80.= A Wheatstone's bridge (Fig. 103), including a scale (No. 100). The aluminum straps, 1, 2, 3, are fastened to a neat wooden base, 10 in. long by 2 in. wide. A No. 28 German-silver wire is used for the bridge.

=No. 81.= A piece of No. 30 uncovered German-silver wire, 2.1 meters long, used for resistance (Fig. 96).

=No. 82.= A piece of No. 28 uncovered German-silver wire, 2.1 meters long.

=No. 83-85.= Three plate binding-posts, consisting of bent straps of sheet aluminum (X, Y, Z, Fig. 96).

=No. 86.= Two ounces of copper sulphate, commonly called bluestone. The crystals may be kept in a large wooden pill box.

=No. 87.= One dozen copper washers.

=No. 88.= One combination rule, 1 ft. long, marked with English and metric systems.

=No. 89.= A hollow coil of No. 24 insulated copper wire (Fig. 130). The spool, on which the wire is wound, has a hole for a five-sixteenths inch core. It is turned down thin, so that the wire is near the core. The coil is about 1-1/8 in. long and 1 in. in diameter. Spring connectors are joined to the ends of the coil.

=No. 90.= A hollow coil of No. 25 insulated copper wire, similar to No. 89, with spring connectors attached to its ends.

=No. 91.= Carbon rod for electroplating.

=No. 92, 93.= Two soft iron cores, with screws (I C, Fig. 130). These cores are 5/16 in. in diameter, and have a threaded hole in one end for fastening them to No. 94.

=No. 94.= A tin box with three holes punched in its top (Fig. 132). This serves as a base, as well as a yoke, for the two electromagnets, A, B, shown in plan.

=No. 95.= Combination connecting plates (Fig. 132). Three aluminum straps are fastened to a wooden base. They are turned up at their ends so that spring connectors can be easily pushed upon them.

=No. 96.= One long iron core (L I C, Fig. 140). This is of soft iron, 5/16 in. in diameter, and long enough to pass through both coils (No. 89, 90).

=No. 97.= Bar magnet, about 4 in. long and 5/16 in. in diameter.

=No. 98.= Coil of insulated wire wound on a soft iron core, to act as a primary coil for induction experiments. This coil fits inside of the hollow coils (Nos. 89, 90).

=No. 99.= A printed degree-card for the galvanoscope (No. 58). This is printed on stiff cardboard, about 3 in. in diameter.

=No. 100.= A printed scale for the Wheatstone's bridge (No. 80). This is printed on stiff paper. The scale is 8 in. long, and is divided into 10 large divisions, each of which is subdivided into 10 parts, thus making 100 parts in all.

INDEX.

Numbers refer to paragraphs. See Table of Contents for the various experiments.

Abreast, arrangement of cells, 365.

Accumulators. (See storage cells.)

Action, local, 273.

Air, as insulator, 144, _a_.

Alternating currents, 443.

Amalgamating, 257, 274.

Amber, 107.

Ammeter, 353.

Ampere, the, 351, 357.

Ampere's rule, 386.

Annealing, 6.

Annunciators, 471.

Anode, 373, 378.

Applications of electricity, Chap. XXVII.

Arc lamp, 485.

Arrangement, of cells, 363 to 368.

Armature, the, 11, 78, 476.

Astatic needles, 251, 253, 254; galvanoscope, 252, 256.

Atmospheric electricity, Chap. XIII., 217; causes of, 221.

Attraction, mutual, 111; and repulsion, laws of magnetic, 29; electric, laws of, 121.

Aurora borealis, 223.

Batteries, Chap. XV.; storage, 382.

Bell, electric, 468.

Bell telephone, 480.

Bichromate cell, 289.

Bound electrification, 162, 191.

Breaking a magnet, 51.

Bridge, Wheatstone's, 324 to 330.

Brushes, 476.

Buzzers, electric, 468.

Cable, submarine, as condenser, 182.

Capacity, inductive, 169; electrical, 176, 178.

Carbon, transmitter, 482; electroscope, 114.

Cathode, 373.

Cell, galvanic, Chap. XV.; arrangement of, 363, 364, 365, 368; chemical action in, 270, 271; direction of current in, 268; local action in, 273; open and closed circuit, 286; polarization of, 278; poles of, 269; simple, 275; secondary, 382; single-fluid, 275; two-fluid, 281, 285; various galvanic, 286 to 291.

Charge, in condenser, 195; residual of condensers, 197.

Charging conductors, Chap. VIII.

Chemical action, 369.

Chemical effects of current, Chap. XXI.

Circuit, electric, 266; divided, 293; short, 295.

Coercive force, 44, 46.

Coils, 390; induction, 473, 474; method of joining, 408; polarity of, 392; resistance, 309; simple resistance, 310.

Commutator, 476.

Compass, 26; our, 32; needle, 243, 249.

Compound magnets, 73.

Condensation of electrification, Chap. X., 178.

Condensers, 178; action of, 186, 191; induction coil, 181; submarine cables, 182.

Conductive discharge, 149, 184.

Conductors, 126, 129, 133; hollow and solid, 153; and insulators, relation between, 133; and non-conductors, 312.

Connections, electrical, 226 to 230.

Contact breaker, Exp. 195; § 466.

Convective discharge, 149.

Copper sulphate solution, 283.

Cores, of electromagnets, 397.

Coulomb, the, 354.

Current electricity, Part III.

Current, 144, _a_, 264; detectors, 232, 239; direction of in cell, 268; direct and alternating, 443; extra, 444; interrupters, 466; primary and secondary, 441; measurement of, 352; reverser, 235, 237; strength of, Chap. XX., 350, 358, 362 to 365; unit of, 351.

Daniell cell, 290.

Declination, 84.

Depolarizers, 280, 282.

Detectors, current, 232, 239.

Diamagnetic bodies, 15.

Dielectric, 184, 191, 195.

Dielectrics, 166.

Dip, 86.

Direct currents, 428, 443.

Dischargers, 188.

Discharges, kinds of, 149.

Divided circuits, 293, 323.

Dry cells, 288.

Dynamo, 435, 476.

Earth's magnetism, 83, 92, 93.

Electric, bells, 468; chime, 193; circuit, 266, Chap. XVI.; current, 144, _a_, 264; density, 155; field, 156; horse-power, 355; lighting, 484; machines, static, 216; motor, 477; polarization, 159; resistance, Chap. XVIII.; wind, 155.

Electricity, static, Part II.; Current, Part III.; Applications of, Chap. XXVII., 456; kinds of, 100; derivation of name, 107; Atmospheric, Chap. XIII., 217.

Electrification, Chap. VI., 103, 116, 132, 134; and heat, 104; condensation of, Chap. X.; escape of, 155; free and bound, 162; induced, Chap. IX.; kinds of, 120; of earth, 222; source of in cells, 265; theories about, 145; two kinds of, 120, 211.

Electrics and non-electrics, 134.

Electrified bodies, 102, 107.

Electrodes, 269.

Electromagnetism, Chap. XXII., 383.

Electromagnets, Chap. XXIII., 396; cores of, 397; horseshoe, 405.

Electromotive force, 144, Chap. XVII., 296, 300, 303; measurement of, Exp. 140; of polarization, 373, 382; series, 301; unit of, 297.

Electrophorus, 138; action of, 171, 172; our, 139.

Electrolysis, 370.

Electrolyte, 370.

Electroplating, 376, 378.

Electroscope, action of, 206, 208; carbon, 114; pith-ball, 200; our leaf, 201, 202.

Electroscopes, Chap. XI.

Electrotyping, 379.

Equator of magnet, 13.

Equipotential points, 326.

External resistance, 307, 368.

Extra current, 444; Exp. 199.

Field, electric, 156; magnetic, Chap. IV., 62, 80; magnets, 476.

Figures, magnetic, 64; permanent, 417.

Force, 103; lines of magnetic, 64, 73, 80, 156; lines of electric, 156; lines of about a wire, 385.

Franklin, Benjamin, 218.

Free electrification, 162.

Frictional electricity, Part II.

Fulminating panes, 180.

Galvanic cells, Chap. XV., 265; chemical action in, 270; various kinds of, 286 to 291.

Galvanoscope, 240 to 249.

Glass, as insulator, 136.

Gold-leaf electroscope, 200, 209.

Gravity cell, 291.

Hardening steel, 8, 10.

Heat, effect on resistance, 343; effect on magnet, 49.

Horse-power, electric, 355.

Horseshoe magnet, 11; advantages of, 82; electromagnets, 405.

Hydrogen, 260, 262, 271, 278, 279, 373.

Inclination of needle, 86.

Induced currents, Chap. XXV.; and work, 429; and lines of force, 432, 435, 438; direction of, 439.

Induced magnetism, Chap. III.

Induction coils, 473; action of, 474; condensers of, 181; with telephone, 483.

Induction, electromagnetic, 426; laws of, 440; static, theory of, 159; successive, 168.

Inductive capacity, 169.

Insulators, Chap. VII., 125.

Internal resistance, 307, 314, 358, 362, 368.

Iron and steel, Chap. I.

Iron, hardening properties of, Exp. 4; impurities of, 1; kinds of, 2; soft, 10.

Jar, Leyden, 179.

Key, 233, 234.

Lamp, arc, 485; incandescent, 486.

Laws, of electrification, 121; of induction, 440; of magnetism, 29; of resistance, 349.

Leclanché cell, 287.

Leyden jar, 179.

Lighting, 484, 485, 486.

Lightning, 144, _a_; 218; rods, 220.

Lines of force, about a wire, 385, 388; electric, 156; and induced currents, 432, 438; magnetic, 64, 73, 74, 80, 156; resistance to, 78, 397.

Local action, 273.

Local currents, 273.

Lodestone, 93.

Magnetic, bodies, 15; circuits, closed, 420; field, 62, 80; figures, permanent, 417; figures, 64, Exp. 161, 162, Exps. 168 to 171; force, lines of, 64, 80, 156; induction of the earth, 92; needle, 26; needles, balancing of, 88; needle, dip of, 86; problems, 33; saturation, 42; screens, 18; tick, Exp. 160; transparency, 18.

Magnetism, Part I.; induced, Chap. III., 53; residual, 44, 53; temporary, 53; terrestrial, Chap. V.; theory of, 42; of earth, 83; laws of, 29.

Magnets, bar, 21; compound, 73; effect of breaking, 51; equator of, 13, 51; experimental, 407; kinds of, 11; natural, 93; poles of, 13, 25; practical uses of, 16.

Mercury, 274.

Motion, production of, Chap. XXVI., 445, 452, 455.

Motors, electric, 477.

Mutual attractions, 111.

Natural magnets, 93.

Needle, astatic, 251, 253, 254; magnetic, 26, 32.

Negative electrification, 120.

Neutral bodies, 102.

Non-conductors, 312.

Non-electrics, 134.

North-seeking poles, 25.

Ohm, the, 308.

Ohm's law, 356.

One-fluid theory, 145.

Open and closed circuits, 266; cells, 286.

Oxygen, 372, 373, 382.

Peltier effect, 424.

Pith-ball electroscope, 200.

Plates or elements, 267.

Polarization of cells, 278; effects of, 279; electric, 159, 164; electromotive force of, 373; magnetic, 56; remedies for, 280.

Poles, 13, 25, 64, 92; consequent, 39; of coils, 392; of electrodes, 269; reversal of, 35; rule for, 31.

Pole pieces, 56.

Positive electrification, 120.

Potential, 133,144; energy, 103.

Primary current, 441.

Proof-plane, 209.

Quantity, unit of, 354.

Recorder, Exp. 197.

Relay, telegraph, 462.

Repulsion, laws of electrostatic, 121; laws of magnetic, 29.

Residual, charge in condenser, 197; magnetism, 44; magnetism of core, Exp. 159.

Resistance, coils, 309; effect of heat on, 343; electrical, Chap. XVIII., 305, 319, 321; external and internal, 307, 362, 368; internal, 314, 358; laws of, 349; to lines of force, 78; measurement of, Chap. XIX.; unit of, 308.

Retentivity, 44, 46.

Reverser, current, 235, 237.

Rheostat, simple, 344.

Saturation, magnetic, 42.

Secondary cells, 382; current, 441.

Self-induction, 444.

Series arrangement of cells, 364.

Shocks, 188.

Short circuits, 295.

Shunts, 293.

Silk, as insulator, 136.

Single-fluid cell, 275.

Single needle telegraph, Exp. 194.

Sounder, telegraph, 458.

Spark, 144, _a_.

Static electricity, Part II.

Static electric machines, 216.

Steel, Chap. I.; kinds of, 2; magnetism of, 42, 46, 49.

St. Elmo's fire, 222.

Storage cells, 382.

Successive, induction, 168; condensation, 199.

Sulphuric acid, 258, 262, 314.

Tangent galvanometer, 352.

Telegraph, line, 459, 460; relay, 462; single needle instrument, Exp. 194; sounder, 458; static, 130.

Telephone, the, 479; Bell, 480; carbon transmitter, 482; with induction coils, 483; receiver, 481.

Tempering steel, 8.

Temporary magnetism, 53.

Terrestrial magnetism, Chap. V.

Thermoelectricity, Chap. XXIV., 423.

Thermopile, 425; home-made, 421.

Thunder, 219.

Transformers, 475.

Transmitters, 480, 482.

Two-fluid cell, 280, 281; care of, 282; chemical action in, 285.

Two-fluid theory of electrification, 146.

Unit of, current strength, 351; E. M. F., 297; of power, 355; quantity, 354; resistance, 308.

Variation, angle of, 84.

Varieties of electricity, 100.

Volt, the, 297.

Voltameters, 297, 353, 380.

Water, composition of, 372.

Watt, the, 355.

Wheatstone's bridge, 324 to 330.

Wind, electric, 155.

Wire tables, Chap. XXVIII.

Yoke, use of, 406.

Zero, potential, 144, _a_.

Zinc, chemical action with, 271; with commercial, 273.

Zinc plates, reasons for amalgamating, 274.

Notes.

Notes.

ELECTRICAL BOOKS ELECTRICAL APPARATUS GAMES PUZZLES EDUCATIONAL AMUSEMENTS

THOMAS M. ST. JOHN, Met. E.

A Word to Parents About Games and Educational Amusements.

Systematic play is as important as systematic work. The best games and home amusements are as valuable to a child as school-studies; in fact, they bring out and stimulate qualities in a child, which no school-study can. Fascinating home amusements are as necessary as school-books.

Boys and girls like to be busy. Their amusements should be entered into as heartily, chosen as carefully, and purchased as willingly as school-books.

=Games.=--JINGO and HUSTLE-BALL are good games.

They are interesting and full of action.

They arouse a child's common-sense.

They cultivate an ability to think rapidly, judge correctly, and decide quickly.

They educate the eye and hand at the same time.

They are very simple, and may be played at once.

=Educational Amusements.=--There is a peculiar fascination about Electricity and Magnetism, which makes these subjects appeal to every boy and girl.

There is nothing better than science studies, to teach children to observe and to see what they look at; besides, it is _fun_ to experiment. "Fun With Electricity" and "Fun With Magnetism" are educational amusements. They contain fascinating experiments and are systematically arranged.

Juvenile Work in Electricity.

_From The Electrical Engineer, May 19, 1898._

The position that Young America is now taking in the electric and magnetic field is very clearly shown at the Electrical Show now being held at Madison Square Garden, by an exhibit of simple experimental apparatus made by young boys from the Browning School, of this city.

The models shown cover every variety of apparatus that is dear to the heart of a boy, and yet, along the whole line from push-buttons to motors, one is struck by the extreme simplicity of design and the ingenious uses made of old tin tomato cans, cracker boxes, bolts, screws, wire, and the wood that a boy can get from a soap box.

The apparatus in this exhibit was made by boys 13, 14 and 15 years of age, from designs made by Mr. Thomas M. St. John, of the Browning School. It clearly shows that good, practical apparatus can be made from cheap materials by an average boy. The whole exhibit is wired and in working order, and it attracts the attention of a large number of parents and boys who hover around to see, in operation, the telegraph instruments, buzzers, shocking coils, current detectors, motors, etc.

Mr. St. John deserves the thanks of every boy who wants to build his own electrical apparatus for amusement or for experimental purposes, as he has made the designs extremely simple, and has kept constantly in mind the fact that the average boy has but a limited supply of pocket money, and an equally limited supply of tools.

How Two Boys Made Their Own Electrical Apparatus.

=CONTENTS:= _Chapter_ I. Cells and Batteries.--II. Battery Fluids and Solutions.--III. Miscellaneous Apparatus and Methods of Construction.--IV. Switches and Cut-Outs.--V. Binding-Posts and Connectors.--VI. Permanent Magnets.--VII. Magnetic Needles and Compasses.--VIII. Yokes and Armatures.--IX. Electro-Magnets.--X. Wire-Winding Apparatus.--XI. Induction Coils and Their Attachments.--XII. Contact Breakers and Current Interrupters.--XIII. Current Detectors and Galvanometers.--XIV. Telegraph Keys and Sounders.--XV. Electric Bells and Buzzers.--XVI. Commutators and Current Reversers.--XVII. Resistance Coils.--XVIII. Apparatus for Static Electricity.--XIX. Electric Motors.--XX. Odds and Ends.--XXI. Tools and Materials.

"The author of this book is a teacher and writer of great ingenuity, and we imagine that the effect of such a book as this falling into Juvenile hands must be highly stimulating and beneficial. It is full of explicit details and instructions in regard to a great variety of apparatus, and the materials required are all within the compass of very modest pocket-money. Moreover, it is systematic and entirely without rhetorical frills, so that the student can go right along without being diverted from good helpful work that will lead him to build useful apparatus and make him understand what he is about. The drawings are plain and excellent. We heartily commend the book."--_Electrical Engineer._

"Those who visited the electrical exhibition last May cannot have failed to notice on the south gallery a very interesting exhibit, consisting, as it did, of electrical apparatus made by boys. The various devices there shown, comprising electro-magnets, telegraph keys and sounders, resistance coils, etc., were turned out by boys following the instructions given in the book with the above title, which is unquestionably one of the most practical little works yet written that treat of similar subjects, for with but a limited amount of mechanical knowledge, and by closely following the instructions given, almost any electrical device may be made at very small expense. That such a book fills a long-felt want may be inferred from the number of inquiries we are constantly receiving from persons desiring to make their own induction coils and other apparatus."--_Electricity._

"At the electrical show in New York last May one of the most interesting exhibits was that of simple electrical apparatus made by the boys in one of the private schools in the city. This apparatus, made by boys of thirteen to fifteen years of age, was from designs by the author of this clever little book, and it was remarkable to see what an ingenious use had been made of old tin tomato-cans, cracker-boxes, bolts, screws, wire, and wood. With these simple materials telegraph instruments, coils, buzzers, current detectors, motors, switches, armatures, and an almost endless variety of apparatus were made. In his book Mr. St. John has given directions in simple language for making and using these devices, and has illustrated these directions with admirable diagrams and cuts. The little volume is unique, and will prove exceedingly helpful to those of our young readers who are fortunate enough to possess themselves of a copy. For schools where a course of elementary science is taught, no better text-book in the first-steps in electricity is obtainable."--_The Great Round World._

Exhibit of Experimental Electrical Apparatus AT THE ELECTRICAL SHOW, MADISON SQUARE GARDEN, NEW YORK.

While only 40 pieces of simple apparatus were shown in this exhibit, it gave visitors something of an idea of what young boys can do if given proper designs.

JUST PUBLISHED.

How Two Boys Made Their Own Electrical Apparatus.

Containing complete directions for making all kinds of simple electrical apparatus for the study of elementary electricity. By PROFESSOR THOMAS M. ST. JOHN, New York City.

The book measures 5 × 7-1/2 in., and is beautifully bound in cloth. It contains 141 pages and 125 illustrations. Complete directions are given for making 152 different pieces of Apparatus for the practical use of students, teachers, and others who wish to experiment.

PRICE, POST-PAID, $1.00.

The shocking coils, telegraph instruments, batteries, electromagnets, motors, etc., etc., are so simple in construction that any boy of average ability can make them; in fact, the illustrations have been made directly from apparatus constructed by young boys.

The author has been working along this line for several years, and he has been able, _with the help of boys_, to devise a complete line of simple electrical apparatus.

_THE APPARATUS IS SIMPLE because the designs and methods of construction have been worked out practically in the school-room, absolutely no machine-work being required._

_THE APPARATUS IS PRACTICAL because it has been designed for real use in the experimental study of elementary electricity._

_THE APPARATUS IS CHEAP because most of the parts can be made of old tin cans and cracker boxes, bolts, screws, wires and wood._

Address, THOMAS M. ST. JOHN, 407 West 51st Street, New York.

Fun With Magnetism.

BOOK AND COMPLETE OUTFIT FOR SIXTY-ONE EXPERIMENTS IN MAGNETISM....

Children like to do experiments; and in this way, better than in any other, _a practical knowledge of the elements of magnetism_ may be obtained.

These experiments, although arranged to amuse boys and girls, have been found to be very _useful in the class-room_ to supplement the ordinary exercises given in text-books of science.

To secure the best _possible quality of apparatus_, the horseshoe magnets were made at Sheffield, England, especially for these sets. They are new and strong. Other parts of the apparatus have also been selected and made with great care, to adapt them particularly to these experiments.--_From the author's preface._

=CONTENTS.=--Experiments With Horseshoe Magnet.--Experiments With Magnetized Needles.--Experiments With Needles, Corks, Wires, Nails, etc.--Experiments With Bar Magnets.--Experiments With Floating Magnets.--Miscellaneous Experiments.--Miscellaneous Illustrations showing what very small children can do with the Apparatus.--Diagrams showing how Magnetized Needles may be used by little children to make hundreds of pretty designs upon paper.

=AMUSING EXPERIMENTS.=--Something for Nervous People to Try.--The Jersey Mosquito.--The Stampede.--The Runaway.--The Dog-fight.--The Whirligig.--The Naval Battle.--A String of Fish.--A Magnetic Gun.--A Top Upsidedown.--A Magnetic Windmill.--A Compass Upsidedown.--The Magnetic Acrobat.--The Busy Ant-hill.--The Magnetic Bridge.--The Merry-go-Round.--The Tight-rope Walker.--A Magnetic Motor Using Attractions and Repulsions.

_The Book and Complete Outfit will be sent, Post-paid, upon receipt of 35 Cents, by_

THOMAS M. ST. JOHN, 407 W. 51st St., New York.

A Few Off-Hand Statements

that have been made about "Fun With Magnetism" and "Fun With Electricity" in letters of inquiry to the author. (These statements were absolutely unsolicited.)

"My little boy has your 'Fun With Magnetism' and enjoys it so much that if the 'Fun With Electricity' is ready I would like to have it for him. Please let me know," etc.

"I have had much fun with 'Fun With Magnetism.'"

"My boy has 'Fun With Magnetism' and has enjoyed it very much and would like the other. Will you," etc.

"Please let me know when 'Fun With Electricity' is upon the market, for if it is as good as this, I shall certainly want it."

"I have just received 'Fun With Magnetism' and am delighted with it. Please send me 12 sets," etc.

"I have 'Fun With Magnetism' and 'Fun With Electricity' and have enjoyed them very much. Please send," etc.

"I am much pleased with 'Fun With Electricity' and would like to have," etc.

"'Fun With Electricity' is fine and I have had lots of fun with it. Please send," etc.

"Having experimented with both of your apparatus 'Fun With Magnetism' and 'Fun With Electricity,' and having found them both amusing and instructive, I wish to ask," etc.

"I have purchased your outfits 'Fun With Electricity' and 'Fun With Magnetism,' and though they are designed for amusement, I find them a great help in my studies. Will you please," etc.

"I have one of your outfits of 'Fun With Electricity,' and I enjoy it very much, some of the experiments being very astonishing. Will you please," etc.

"I have enjoyed 'Fun With Magnetism' and 'Fun With Electricity' very much."

"My little boy has your book 'Fun With Electricity,' which has given him much amusement. He would like to have," etc.

"I am very much pleased with both outfits. I am very much in favor of such things for boys; it keeps them occupied with something that is both amusing and instructive. Send me," etc.

Fun With Electricity.

BOOK AND COMPLETE OUTFIT FOR SIXTY EXPERIMENTS IN ELECTRICITY....

Enough of the principles of electricity are brought out to make the book instructive as well as amusing. The experiments are systematically arranged, and make a fascinating science course. No chemicals, no danger.

The book is conversational and not at all "schooly," Harry and Ned being two boys who perform the experiments and talk over the results as they go along.

"The book reads like a story."--"An appropriate present for a boy or girl."--"Intelligent parents will appreciate 'Fun With Electricity.'"--"Very complete, because it contains both book and apparatus."--"There is no end to the fun which a boy or girl can have with this fascinating amusement."

=THERE IS FUN IN THESE EXPERIMENTS.=--Chain Lightning.--An Electric Whirligig.--The Baby Thunderstorm.--A Race with Electricity.--An Electric Frog Pond.--An Electric Ding-Dong.--The Magic Finger.--Daddy Long-Legs.--Jumping Sally.--An Electric Kite.--Very Shocking.--Condensed Lightning.--An Electric Fly-Trap.--The Merry Pendulum.--An Electric Ferry-Boat.--A Funny Piece of Paper.--A Joke on the Family Cat.--Electricity Plays Leap-Frog.--Lightning Goes Over a Bridge.--Electricity Carries a Lantern.--And _=40 Others=_.

The _=OUTFIT=_ contains 20 different articles. The _=BOOK OF INSTRUCTION=_ measures 5 × 7-1/2 inches, and has 38 illustrations, 55 pages, good paper and clear type.

_The Book and Complete Outfit will be sent, by mail or express, Charges Prepaid, upon receipt of 65 Cents, by_

THOMAS M. ST. JOHN, 407 W. 51st St., New York.

Fun With Puzzles.

BOOK, KEY, AND COMPLETE OUTFIT FOR FOUR HUNDRED PUZZLES....

The BOOK measures 5 × 7-1/2 inches. It is well printed, nicely bound, and contains 15 chapters, 80 pages, and 128 illustrations. The KEY is illustrated. It is bound with the book, and contains the solution of every puzzle. The COMPLETE OUTFIT is placed in a neat box with the book. It consists of numbers, counters, figures, pictures, etc., for doing the puzzles.

=CONTENTS=: _Chapter_ (1) Secret Writing. (2) Magic Triangles, Squares, Rectangles, Hexagons, Crosses, Circles, etc. (3) Dropped Letter and Dropped Word Puzzles. (4) Mixed Proverbs, Prose and Rhyme. (5) Word Diamonds, Squares, Triangles, and Rhomboids. (6) Numerical Enigmas. (7) Jumbled Writing and Magic Proverbs. (8) Dissected Puzzles. (9) Hidden and Concealed Words. (10) Divided Cakes, Pies, Gardens, Farms, etc. (11) Bicycle and Boat Puzzles. (12) Various Word and Letter Puzzles. (13) Puzzles with Counters. (14) Combination Puzzles. (15) Mazes and Labyrinths.

"Fun With Puzzles" is a book that every boy and girl should have. It is amusing, instructive,--educational. It is just the thing to wake up boys and girls and make them think. They like it, because it is real fun. This sort of educational play should be given in every school-room and in every home.

"Fun With Puzzles" will puzzle your friends, as well as yourself; it contains some real brain-splitters. Over 300 new and original puzzles are given, besides many that are hundreds of years old.

=Secret Writing.= Among the many things that "F. W. P." contains, is the key to _secret writing_. It shows you a very simple way to write letters to your friends, and it is simply impossible for others to read what you have written, unless they know the secret. This, alone is a valuable thing for any boy or girl who wants to have some fun.

_The Book, Key, and Complete Outfit will be sent, postpaid, upon receipt of 35 cents, by_

THOMAS M. ST. JOHN, 407 West 51st St., New York City.

Fun With Soap-Bubbles.

BOOK AND COMPLETE OUTFIT FOR FANCY BUBBLES AND FILMS....

=THE OUTFIT= contains everything necessary for thousands of beautiful bubbles and films. All highly colored articles have been carefully avoided, as cheap paints and dyes are positively dangerous in children's mouths. The outfit contains the following articles:

One Book of Instructions, called "Fun With Soap-Bubbles," 1 Metal Base for Bubble Stand, 1 Wooden Rod for Bubble Stand, 8 Large Wire Rings for Bubble Stand, 1 Small Wire Ring, 3 Straws, 1 Package of Prepared Soap, 1 Bubble Pipe, 1 Water-proof Bubble Horn. The complete outfit is placed in a neat box with the book. (Extra Horns, Soap, etc., furnished at slight cost.)

=CONTENTS OF BOOK.=--Twenty-one Illustrations.--Introduction.--The Colors of Soap-bubbles.--The Outfit.--Soap Mixture.--Useful Hints.--Bubbles Blown With Pipes.--Bubbles Blown With Straws.--Bubbles Blown With the Horn.--Floating Bubbles.--Baby Bubbles.--Smoke Bubbles.--Bombshell Bubbles.--Dancing Bubbles.--Bubble Games.--Supported Bubbles.--Bubble Cluster.--Suspended Bubbles.--Bubble Lamp Chimney.--Bubble Lenses.--Bubble Basket.--Bubble Bellows.--To Draw a Bubble Through a Ring.--Bubble Acorn.--Bubble Bottle.--A Bubble Within a Bubble.--Another Way.--Bubble Shade.--Bubble Hammock.--Wrestling Bubbles.--A Smoking Bubble.--Soap Films.--The Tennis Racket Film.--Fish-net Film.--Pan-shaped Film.--Bow and Arrow Film.--Bubble Dome.--Double Bubble Dome.--Pyramid Bubbles.--Turtle-back Bubbles.--Soap-bubbles and Frictional Electricity.

"There is nothing more beautiful than the airy-fairy soap-bubble with its everchanging colors."

_=THE BEST POSSIBLE AMUSEMENT FOR OLD AND YOUNG.=_

_The Book and Complete Outfit will be sent, POST-PAID, upon receipt of 35 cents, by_

THOMAS M. ST. JOHN, 407 West 51st St., New York City.

Things A Boy Should Know About Electricity.

(In Preparation.)

This book explains, in simple, straightforward language, many things about electricity; things in which the American boy is intensely interested; things he wants to know; things he should know.

It is free from technical language and rhetorical frills, but it tells how things work, and why they work.

It is brimful of illustrations--the best that can be had--illustrations that are taken directly from apparatus and machinery, and that show what they are intended to show.

This book does not contain experiments, or tell how to make apparatus; our other books do that. After explaining the simple principles of electricity, it shows how these principles are used and combined to make electricity do every-day work. The following are

_Some of the Things Electricity Can Do:_

It signals without wires.

It drills rock, coal, and teeth.

It cures diseases and kills criminals.

It protects, heats, and ventilates houses.

It photographs the bones of the human body.

It rings church bells and plays church organs.

It lights streets, cars, boats, mines, houses, etc.

It pumps water, cooks food, and fans you while eating.

It runs all sorts of machinery, elevators, cars, boats, and wagons.

It sends messages with the telegraph, telephone, telautograph, and search-light.

It cuts cloth, irons clothes, washes dishes, blackens boots, welds metals, prints books, etc., etc.

_Everyone Should Know About Electricity._

=Things A Boy Should Know About Electricity= will interest _you_. We shall be glad to send you complete information as soon as it is ready. Send us your address now.

Dewey Flag Poles

=ARE LITTLE MODELS OF REAL FLAG POLES....=

They are appropriate for any occasion, and suitable for any kind of decoration. They should stand on tables, mantels, pianos, etc.; in fact, there is no better ornament for general use.

"They should be in every home and in every school-room in the United States."

"No toy fort complete without a Dewey Flag Pole."

"The children can fasten them on the windowsill and watch them flutter by the hour."

"They hoist like big flags, at half-mast, etc."

"Invaluable for store-window decoration."

PRICES

SMALL SIZE: height 18 inches, fitted with United States or Cuban Silk Flag (4×6 in.) post-paid, 30c.

LARGE SIZE: height 24 inches, fitted with United States Silk Flag (7 × 10 in.), post-paid, 40c.

LARGE SIZE: fitted with Cuban or British Silk Flag (8×12 in.), post-paid, 50c.

_DEWEY FLAG POLES are beautifully made of hard wood, and fitted with best Silk Flags_.

GAMES.

Hustle=Ball.

A quick, sharp, decisive game that is thoroughly American.

Played by means of Magic Wands, and Polished Balls of Steel.

_=Needed:= "A quick eye and a nimble hand."_--_Shakespeare_.

_The Rule: Just keep cool--and hustle._

Four Games with One Outfit:

"Hustle Ball," "Leap-Frog," "Cross-Country Race," "Magnetic Potato-Race."

The game-board is new and original, as well as the methods of playing. The game is put up in a strong box having a beautifully lithographed cover, and measures 8 × 15-1/2 inches. With the game-board are furnished, magic wands, polished steel balls, an "extra strength" horseshoe magnet, and a complete set of illustrated rules and directions for playing.

"Unlike all other games." "Any one can play Hustle-Ball." "Just the thing for progressive parties." "Hustle-Ball games are intensely exciting." "No waiting for some one to play." "You win or lose a point in a few seconds." "By handicapping the best players, all games are made equally interesting and exciting." "A game for Grandparents, as well as for Grandchildren."

A Brand-New Idea in Games.

'_A HUSTLE FROM THE WORD GO._'

_=This Exciting Game=_ will be sent, _=Charges Prepaid=_, by mail or express, upon receipt of 65 Cents.

Address THOMAS M. ST. JOHN, 407 West 51st Street, New York City.

JINGO

THE GREAT WAR GAME

Social Exciting Interesting Simple.

A Thorough War Game:--Infantry Against Infantry, Cavalry Against Cavalry, Etc.

Jingo is really a great war contest between England and America. Upon the game-board are 14 beautiful war scenes, each lithographed in 8 colors. American and English flags, coats of arms, cannon, torpedoes, etc., aid in making this game artistic, handsome and attractive. The following companies, ships, etc., are shown:--_American_, 12th U. S. Infantry,--6th U. S. Cavalry,--2d U. S. Light Artillery,--U. S. Mortar Battery,--U. S. Monitor "Miantonomoh,"--U. S. Ram "Katahdin,"--U. S. Battleship "Indiana,"--U. S. Torpedo Boat "Cushing,"--U. S Dynamite Cruiser "Vesuvius." _English_, 30th East Lancashire,--1st Royal Dragoons,--Royal Horse Artillery,--Royal Artillery,--H. M. S. "Thunderer,"--H. M. S. "Seagull,"--H. M. S. "Nile,"--H. M. S. "Australia,"--H. M. S. "Dart."

The game board is over 16 inches square when opened. Jingo is made and finished in a manner which makes it the most beautiful, artistic, and practical game ever published.

"Just what every boy likes." "A good idea well carried out." "The Game-board is a work of art." "Any child can play Jingo at once." "It is the handsomest game on the market."

JINGO JUNIOR is the Greatest Game ever Invented for Little Folks.

It is played upon the Jingo board with the extra ammunition furnished.

These Two Great Games make a most complete and beautiful outfit for home amusement.

JINGO AND JINGO JUNIOR.

Two Fascinating and Entirely Different Games, Played with One Outfit, and Complete in One Box.

_THIS HANDSOME OUTFIT_ for playing the _TWO GREAT WAR GAMES_ will be sent _CHARGES PREPAID_ upon receipt of _=$1.00=_.

Address THOMAS M. ST. JOHN, 407 West 51st Street, New York City.

Transcriber's Notes

In the text version, Italic text is denoted by _underscores_ and bold text by =equal signs=.

Obvious punctuation errors have been repaired.

The book contains some inconsistent hyphenation which has been left as printed.

p. xi. (TOC) "constructiou" changed to "construction"

p. xiv. (TOC) "The Prodution of Motion" changed to "The Production of Motion"

p. 27. para. 73. "thick permament magnets" changed to "thick permanent magnets"

p. 99. para 253. "wabble" may be a typo for wobble but has been left on the off chance that this could be what was intended.

p. 118. Fig 91. The final column has been scored through but appears to read "CU to ZN"

p. 131. para. 324, 325. German-silver Wire, G-s W used here but previously G S W used.

p. 164. para 395. "circuit in closed" changed to "circuit is closed"

p. 166. para 398. "core inside of the c l" changed to "core inside of the coil" after checking original scans.

p. 169-170. It appears that a word has been omitted across the page break. "The copper washer, C W, be used." has been changed to "The copper washer, C W, should be used.". (Alternative words are possible!)

p. 211. No. 35. 5-16 in. changed to 5/16 in.

p. 213. No. 92, 93. 5-16 in. changed to 5/16 in.

p. 214. No. 96. and No. 97. 5-16 in. changed to 5/16 in.

p. 216. Entry for Coulomb moved from end of "C" to above Current.