ratio of the circumference of a circle to its diameter =3.1416 [Greek: pi]

reactance X

resistance R

time t

velocity v

velocity of light c

wave length [Greek: lambda]

wave length in meters [Greek: lambda]m

work W

permeability [Greek: mu]

Square root [Math: square root]

TABLE OF ENAMELED WIRE

No. of Turns Turns Ohms per Wire, per per Cubic Inch B.& S. Linear Square of Gauge Inch Inch Winding

20 30 885 .748

22 37 1400 1.88

24 46 2160 4.61

26 58 3460 11.80

28 73 5400 29.20

30 91 8260 70.90

32 116 21,000 7547.00

34 145 13,430 2968.00

36 178 31,820 1098.00

38 232 54,080 456.00

40 294 86,500 183.00

TABLE OF FREQUENCY AND WAVE LENGTHS

W. L.--Wave Lengths in Meters. F.--Number of Oscillations per Second. O. or square root L. C. is called Oscillation Constant. C.--Capacity in Microfarads. L.--Inductance in Centimeters. 1000 Centimeters = 1 Microhenry.

W.L. F O L.C. 50 6,000,000 .839 .7039 100 3,000,000 1.68 2.82 150 2,000,000 2.52 6.35 200 1,500,000 3.36 11.29 250 1,200,000 4.19 17.55 300 1,000,000 5.05 25.30 350 857,100 5.87 34.46 400 750,000 6.71 45.03 450 666,700 7.55 57.00 500 600,000 8.39 70.39 550 545,400 9.23 85.19 600 500,000 10.07 101.41 700 428,600 11.74 137.83 800 375,000 13.42 180.10 900 333,300 15.10 228.01 1,000 300,000 16.78 281.57 1,100 272,730 18.45 340.40 1,200 250,000 20.13 405.20 1,300 230,760 21.81 475.70 1,400 214,380 23.49 551.80 1,500 200,000 25.17 633.50 1,600 187,500 26.84 720.40 1,700 176,460 28.52 813.40 1,800 166,670 30.20 912.00 1,900 157,800 31.88 1,016.40 2,000 150,000 33.55 1,125.60 2,100 142,850 35.23 1,241.20 2,200 136,360 36.91 1,362.40 2,300 130,430 38.59 1,489.30 2,400 125,000 40.27 1,621.80 2,500 120,000 41.95 1,759.70 2,600 115,380 43.62 1,902.60 2,700 111,110 45.30 2,052.00 2,800 107,140 46.89 2,207.00 2,900 103,450 48.66 2,366.30 3,000 100,000 50.33 2,533.20 4,000 75,000 67.11 4,504.00 5,000 60,000 83.89 7,038.00 6,000 50,000 100.7 10,130.00 7,000 41,800 117.3 13,630.00 8,000 37,500 134.1 18,000.00 9,000 33,300 151.0 22,820.00 10,000 30,000 167.9 28,150.00 11,000 27,300 184.8 34,150.00 12,000 25,000 201.5 40,600.00 13,000 23,100 218.3 47,600.00 14,000 21,400 235.0 55,200.00 15,000 20,000 252.0 63,500.00 16,000 18,750 269.0 72,300.00

PRONUNCIATION OF GREEK LETTERS

Many of the physical quantities use Greek letters for symbols. The following is the Greek alphabet with the way the letters are pronounced:

a alpha b beta g gamma d delta e epsilon z zeta ae eta th theta i iota k kappa l lambda m mu n nu x Xi(Zi) o omicron p pi r rho s sigma t tau u upsilon ph phi ch chi ps psi o omega

TABLE OF SPARKING DISTANCES

In Air for Various Voltages between Needle Points

Volts Distance Inches Centimeter 5,000 .225 .57 10,000 .470 1.19 15,000 .725 1.84 20,000 1.000 2.54 25,000 1.300 3.30 30,000 1.625 4.10 35,000 2.000 5.10 40,000 2.450 6.20 45,000 2.95 7.50 50,000 3.55 9.90 60,000 4.65 11.8 70,000 5.85 14.9 80,000 7.10 18.0 90,000 8.35 21.2 100,000 9.60 24.4 110,000 10.75 27.3 120,000 11.85 30.1 130,000 12.95 32.9 140,000 13.95 35.4 150,000 15.00 38.1

FEET PER POUND OF INSULATED MAGNET WIRE

No. of Single Double Single Double B.& S. Cotton, Cotton, Silk, Silk, Enamel Gauge 4-Mils 8-Mils 1-3/4-Mils 4-Mils

20 311 298 319 312 320 21 389 370 408 389 404 22 488 461 503 498 509 23 612 584 636 631 642