APPENDICES

APPENDIX A SOME USEFUL MATHEMATICAL FORMULAS

π = 3.14159 (π is a Greek letter pronounced Pi)

d = diameter of a circle

r = radius of a circle

p = periphery, or circumference of a circle

The area of a circle = πr²

The circumference of a circle = πd

The diameter of a circle = p = p

π 3.14

The radius of a circle = p = p

2π 6.28

The surface of a sphere = 4πr² = πd²

The volume of a sphere = 4 πr³ = 1 πd³

3 6

APPENDIX B THE METRIC OR DECIMAL SYSTEM

The metric system is a French system of weights and measures much used in the arts and sciences in every civilized country and as each unit is multiplied or divided by 10 to obtain ascending or descending values it is much more convenient to use than the older English system of arbitrary measures.

The metric system is based on the meter, which is one-ten millionth of the distance from the Earth’s equator to the North Pole. There are five units, the four latter being derived from the meter and these are:

1. The meter which is the unit of length and is about 3.280 feet in length.

2. The are which is the unit of surface and is 100 square meters in area.

3. The liter which is the unit of capacity and is 1 cubic decimeter, which is equal to 1.0567 United States quarts.

4. The stere which is the unit of solidity and is equal to 1 cubic meter.

5. The gram is the unit of weight and is the weight of 1 cubic centimeter of distilled water at its maxim density.

APPENDIX C METRIC MEASURES OF LENGTH AND VALUES IN INCHES

Divisions Millimeter (mm) = 0.001 m. = 0.03937 inch

Centimeter (cm) = 0.01 m. = 0.3937 inch

Decimeter (dm) = 0.1 m. = 3.937 inches

Unit Meter (m) = 1. m. = 39.37 inches

Multiples Dekameter (Dm) = 10. m. = 393.7 inches

Hektometer (Hm) = 100. m. = 328. feet and 1 inch

Kilometer (Km) = 1,000. m. = 0.62326 mile

Myriameter (Mm) = 10,000. m. = 6.2326 miles

APPENDIX D METRIC MEASURES OF WEIGHT AND VALUES IN ENGLISH WEIGHT

Divisions Milligram (mg) = 0.001 g = 0.0154 grain avoirdupois

Centigram (cg) = 0.01 g = 0.1543 grain “

Decigram (dg) = 0.1 g = 1.5432 grain “

Unit Gram (g) = 1 g = 15.432 grains “

Multiples Dekagram (Dg) = 10 g = 0.3527 ounce “

Hektogram (Hg) = 100 g = 3.5274 ounces “

Kilogram (Kg) = 1,000 g = 2.2046 pounds “

Myriagram (Mg) = 10,000 g = 22.046 pounds “

APPENDIX E TO CHANGE METRIC TO ENGLISH MEASURE AND VICE VERSA

To Change To Multiply by

Inches Centimeters 2.54

Feet Meters 0.3048

Miles Kilometers 1.6093

Square Inches Square Centimeters 6.4516

Square Feet Square Meters 0.0929

Square Yards Square Meters 0.8361

Cubic Inches Cubic Centimeters 16.3872

Cubic yards Cubic Meters 0.7646

Fluid ounces Cubic Centimeters 29.574

Quarts Liters 0.9464

Ounces (avoirdupois) Grams 28.3495

Grains Milligrams 64.789

Pounds (avoirdupois) Kilograms 0.4536

Meters Inches 39.37

Meters Feet 3.2808

Kilometers Miles 0.6213

Square Centimeters Square Inches 0.155

Square Meters Square Yards 1.196

Cubic Centimeters Cubic Inches 0.0610

Cubic Meters Cubic Yards 1.308

Cubic Centimeters Fluid Ounces 0.0344

Liters Quarts 1.0567

Grams Grains 15.4324

Kilograms Pounds 2.204

APPENDIX F SIZES OF TWIST DRILLS FOR TAPS OR SCREWS

No. of Drill No. of Tap or Screw No. of Threads to the Inch

Use 38 for 4 — 36

“ 32 “ 6 — 32

“ 28 “ 8 — 32

“ 22 “ 10 — 24

“ 13 “ 12 — 24

APPENDIX G SIZES OF TAPS AND DIES

No. of Tap or Die Threads to Inch

4 36

6 32

8 32

10 24

12 24

APPENDIX H SIZES OF MACHINE SCREWS AND NUTS

Machine screws and nuts are numbered the same as dies and taps.

APPENDIX I REDUCING FRICTION

When two bodies are rubbed together the motion is opposed by a force called friction. When two surfaces slide against each other the friction between them is proportional to the force pressing them together. The amount of friction depends upon the pressure of the bodies, the roughness of their surfaces and also slightly on their adhesion. The friction is the same regardless of the speed with which the surfaces slide over each other.

The co-efficient of friction is the measure of friction and this is found by dividing the force of friction by the force pressing the surfaces together. Here are a few co-efficients of sliding friction:

Per cent.

Oak on Oak with Fibers parallel without lubricant 0.42

Oak on Oak with Fibers parallel rubbed with soap 0.16

Cast Iron on Oak 0.42

Cast Iron on Cast Iron, not lubricated 0.15

Cast Iron on Cast Iron, lubricated 0.10

Iron on Brass 0.16

Brass on Brass 0.20

Iron on Bronze, without lubricant 0.25

Iron on Bronze, thoroughly lubricated 0.06

Cast Iron Wheels on Rails (Rolling Friction) 0.004

Ball Bearings (Rolling Friction) 0.001

APPENDIX J WEIGHT OF CASTINGS COMPARED WITH WOOD PATTERNS

The following table shows what the weight of a casting will be compared with the weight of the wood pattern from which it was made, less the weight of the core point, or piece projecting from the pattern to support it.

A Wood Pattern Weighing One Pound Will Make a Casting Weighing

Pattern of Cast Iron Pounds Brass Pounds Copper Pounds Bronze Pounds Zinc Pounds

Pine 14 15.8 16.7 16.3 13.5

Beech 9.7 10.9 11.4 11.3 9.1

Oak 9 10.1 10.4 10.3 12.9

Birch 10.6 11.9 12.3 12.2 10.2

Mahogany 11.7 13.2 13.7 13.5 11.2

Brass 0.84 0.95 0.99 0.98 0.81

APPENDIX K GEARS AND GEARINGS

A spur-gear is a gear with teeth cut on its periphery, that is an ordinary cog-wheel. Miter gears are two bevel gears of the same diameter which run together. A large miter gear will not mesh with a small miter gear nor with another bevel gear in the proper manner. Miter and bevel gears cannot be interchanged with other sets like spur gears.

Fig. 129. CROSS SECTION OF GEAR

All miter gears that you buy ready cut are made so that their shafts run at right angles to each other as shown in Fig. 129, but you can have them cut to order to run at any angle you want.

To find the pitch, pitch diameter, circular pitch, etc., of both spur and bevel gears use these rules:

π = 3.14159

p = pitch

n = number of teeth

pd = pitch diameter

od = outside diameter

cp = circular pitch

To Find the Pitch:

p = n

pd

To Find the Number of Teeth:

n = p × pd

To Find the Pitch Diameter:

pd = n

p

To Find the Outside Diameter of Spur Wheels:

od = (2 + n)

p

To Find the Circular Pitch:

cp = π

pd

To Find the Distance Between the Centers of Two Spur Gears:

(n¹ + n²)

2

p

Where n¹ + n² = the sum of the teeth of both gears.

APPENDIX L SOME USEFUL ALLOYS

Name of Alloy Parts of Copper Parts of Tin Parts of Zinc Parts of Lead Parts of Other Metals

Gun Metal 91 9

Bell Metal 75 25

Phosphor Bronze 92½ 7 ½ phosphorus

Aluminum Bronze 90 10 aluminum

Common Brass 66⅔ 33⅓

Brazing Metal (soft) 50 12½ 37½

German Silver 60 20 20 nickel

Common Solder 50 50

Fine Solder 66⅔ 33⅓

Babbitt Metal 3 89 8 antimony

Pewter 80 20

Type Metal 80 20 antimony

Aluminum Solder 95 5 bismuth

Magnetic Alloy.—An alloy that has strong magnetic properties is made of 25 parts of manganese, 14 parts of aluminum and 61 parts of copper, yet none of these metals are even slightly magnetic.

APPENDIX M SOME HARD SOLDERS

Hard solders melt only at red heat and are used for soldering gold, silver, brass and other metals where a good strong joint is needed.

Metal to be Soldered Parts of Gold Parts of Brass Parts of Silver Parts of Zinc Parts of Other Metals

Gold 66.67 22.22 11.11 copper

Silver 43.75 50 6.25

Brass 87.5 12.5

APPENDIX N HIGH SPEED STEEL

A special steel alloy which is largely used for turning tools in engine lathes and which will cut ordinary steel when the latter is revolved at a high surface velocity is called high speed steel. A tool made of high speed steel will not lose its temper and will keep its cutting edge hour after hour if they are kept cool by a stream of water running on them. A good high speed steel for machine tools is known by the trade name of blue-chip and is manufactured by the Firth-Sterling Steel Company of Pittsburg, Pa.

APPENDIX O

SOME ELECTRICAL SYMBOLS, TERMS AND FORMULAS

Symbols Terms

E or EMF = Electromotive Force

I = Intensity of Current

R = Resistance

C = Capacity

Q = Quantity of Current

= Magneto-Motive Force

= Reluctance (magnetic resistance)

µ = Magnetic Permeability

W = Electric Energy

P = Electric Power

SOME DEFINITIONS

E or EMF, or electromotive force, is the force that moves a current through a conductor.

I, or intensity of current, or current as it is called for short, is the flow of electricity through a conductor.

R, or resistance is that property of a conductor which opposes the flow of the current.

SOME ELECTRICAL UNITS

Practical Units. Electrical Quantity

Volt is the practical unit of EMF

Ampere is the practical unit of I

Ohm is the practical unit of R

Watt is the practical unit of P

OHM’S LAW

Since the intensity of an electric current varies directly as the electromotive force and inversely as the resistance, if you know the value of any two of the above units you can easily find the third.

Amperes = Volts , or I = E

Ohms R

Electromotive Force = Current , or E = I

Resistance R

Resistance = Electromotive Force , or R = E

Current I

To Find Power of an Electric Current in Terms of Horse Power

One Watt = 1 volt × 1 ampere

746 Watts = 1 horse power.

To find the power of an electric current in terms of horse-power, find the number of watts by multiplying the volts by the amperes and divide the watts by 746 and the result will give you the horse-power of the current.

APPENDIX P NUMBER, DIAMETER, CAPACITY, WEIGHT, AND RESISTANCE OF PURE COPPER WIRE

Gage, B. & S. No. Diameter in 1000ths. Sectional Area in Circular Mils. Capacity in Amperes OHMS FEET POUNDS

Per 1,000 feet Per Mile Per Pound Per Pound Per Ohm Per 1,000 feet Per Ohm

0000 .460 211600. 312. .0490 .2590 .00007 1.5612 20497.7 640.59 12987.

000 .40964 167805. 262. .0618 .3266 .00012 1.9687 16255.27 507.85 8333.

00 .3648 133079. 220. .0780 .4118 .00019 2.4824 12891.37 402.83 5263.

0 .32486 105534. 185. .0983 .5190 .00031 3.1303 10223.08 319.45 3225.

1 .2893 83694. 156. .1240 .6549 .00049 3.9471 8107.49 253.34 2041.

2 .25763 66373. 131. .1564 .8258 .00078 4.9772 6429.58 200.91 1228.

3 .22942 52634. 110. .1972 1.0414 .00125 6.2765 5098.61 159.32 800.

4 .20431 41473. 92.3 .2486 1.313 .00198 7.9141 4043.6 126.35 505.

5 .18194 33102. 77.6 .3136 1.655 .00314 9.9798 3206.61 100.20 318.

6 .16202 26251. 65.2 .3954 2.088 .00499 12.5847 2542.89 79.462 200.

7 .14428 20817. 54.8 .4987 2.633 .00792 15.8696 2015.51 63.013 126.

8 .12849 16510. 46.1 .6529 3.3 .0125 20.0097 1599.3 49.976 80.

9 .11443 13094. 38.7 .7892 4.1 .0197 25.229 1268.44 39.636 50.

10 .10189 10382. 32.5 .8441 4.4 .0270 31.8212 1055.66 31.426 37.

11 .09074 8234. 27.3 1.254 6.4 .0501 40.1202 797.649 24.924 20.

12 .08080 6530. 23. 1.580 8.3 .079 50.5906 632.555 19.766 12.65

13 .07196 5178. 19.3 1.995 10.4 .127 63.7948 501.63 15.674 7.87

14 .06408 4107. 16.2 2.504 13.2 .200 80.4415 397.822 12.435 5.00

15 .05706 3257. 13.6 3.172 16.7 .320 101.4365 315.482 9.859 3.12

16 .05082 2583. 11.5 4.001 23. .512 127.12 250.184 7.819 1.95

17 .04525 2048. 9.6 5.04 26. .811 161.29 198.409 6.199 1.23

18 .04030 1624. 8.1 6.36 33. 1.29 203.374 157.35 4.916 .775

19 .03589 1288. 8.25 43. 2.11 256.468 124.777 3.899 .473

20 .03196 1021. 10.12 53. 3.27 323.399 98.9533 3.094 .305

21 .02846 810. 12.76 68. 5.20 407.815 78.473 2.452 .192

22 .02534 642. 16.25 85. 8.35 514.193 62.236 1.945 .119

23 .02257 509. 20.30 108. 13.3 648.452 49.3504 1.542 .075

24 .0201 404. 25.60 135. 20.9 817.688 39.1365 1.223 .047

25 .0179 320. 32.2 170. 32.2 1031.038 31.0381 .9699 .030

26 .01594 254. 40.7 214. 52.9 1300.180 24.6131 .7692 .0187

27 .01419 201. 51.3 270. 84.2 1639.49 19.5191 .6099 .0118

28 .01264 159.8 64.8 343. 134. 2067.364 15.4793 .4807 .0074

29 .01125 126.7 81.6 432. 213. 2606.959 12.2854 .3835 .0047

30 .01002 100.5 103. 538. 338. 3287.084 9.7355 .3002 .0029

31 .00892 79.7 130. 685. 539. 4414.49 7.7214 .2413 .0018

32 .00795 63. 164. 865. 856. 5226.915 6.1224 .1913 .0011

33 .00708 50.1 206. 1033. 1357. 6590.41 4.8557 .1517 .00076

34 .00630 39.74 260. 1389. 2166. 8312.8 3.8496 .1204 .00046

35 .00561 31.5 328. 1820. 3521. 10481.77 3.0530 .0956 .00028

36 .005 25. 414. 2200. 5469. 13214.16 2.4217 .0757 .00018

37 .00445 19.8 523. 2765. 8742. 16659.97 1.9208 .0600 .00011

38 .00396 15.72 660. 3486. 13722. 21013.25 1.5229 .0475 .00007

39 .00353 12.47 832. 4395. 21896. 26496.237 1.2077 .0375 .00004

40 .00314 9.88 1049. 5542. 34823. 33420.63 0.9798 .0299 .00002

APPENDIX Q NUMBER OF TURNS OF WIRE THAT CAN BE WOUND IN A GIVEN SPACE

No. B. & S. or American Gage COTTON SILK

SINGLE DOUBLE SINGLE DOUBLE

Per Square Inch. Per Square Qu. Inch Per Square Inch. Per Square Qu. Inch Per Square Inch. Per Square Qu. Inch Per Square Inch. Per Square Qu. Inch

20 676 42 576 36 841 52 676 42

21 842 53 625 39 961 60 842 53

22 1.024 64 729 45 1.225 76 1.024 64

23 1.024 81 900 56 1.521 95 1.296 81

24 1.600 100 1.089 68 1.936 121 1.600 100

25 1.849 115 1.296 81 2.304 144 1.849 115

26 2.209 138 1.440 90 2.916 182 2.209 138

27 2.500 156 1.600 100 3.249 206 2.500 156

28 3.025 189 1.849 115 4.096 254 3.025 189

29 3.481 218 2.025 126 4.761 297 3.481 218

30 4.356 272 2.500 156 6.400 400 4.356 272

31 5.001 315 2.704 169 7.769 485 5.041 315

32 5.929 370 3.025 189 9.025 564 5.929 370

33 7.089 443 3.481 218 11.025 689 7.089 443

34 7.769 485 3.600 225 12.321 770 7.769 485

35 8.100 506 3.844 240 13.689 855 8.100 506

36 10.000 625 4.356 272 17.689 1.105 10.000 625

37 11.025 689 4.761 297 20.164 1.240 11.025 689

38 12.321 770 5.041 315 23.716 1.482 12.321 770

39 13.689 855 5.476 342 27.556 1.722 13.689 855

40 15.625 976 5.929 370 32.761 2.047 15.625 976

(W. J. Clarke.)

APPENDIX R PRICES OF SINGLE AND DOUBLE SILK AND COTTON COVERED MAGNET WIRE

PRICE PER POUND

Size by B. & S. Gage Single Covered. Double Covered.

Cotton Silk Cotton Silk

16 $0.80 $1.02

17 .82 1.04

18 .84 1.06

19 .86 1.08

20 $0.58 .88 $0.64 1.12

21 .60 .90 .70 1.15

22 .62 .92 .74 1.22

23 .65 .96 .78 1.28

24 .68 1.02 .84 1.38

25 .73 1.10 .92 1.48

26 .80 1.20 1.00 1.65

27 .86 1.30 1.10 1.85

28 .92 1.40 1.20 2.00

29 .98 1.53 1.30 2.22

30 1.08 1.70 1.42 2.56

31 1.19 1.92 1.54 3.08

32 1.27 2.16 1.64 3.40

33 1.44 2.46 1.88 4.00

34 1.73 2.90 2.20 4.60

35 1.86 3.38 2.67 5.28

36 2.12 3.93 3.00 5.98

37 2.70 4.66 4.30 7.37

38 3.60 5.58 5.70 8.43

39 4.70 6.76 7.20 9.75

40 6.00 8.14 9.00 11.53

There is a discount of about 50 per cent. on the above prices though this is subject to change.

APPENDIX S A LIST OF SOME CHEMICAL ELEMENTS AND THEIR SYMBOLS

Element Symbol

Aluminum Al

Antimony Sb

Argon A

Arsenic As

Barium Bi

Boron B

Bromine Br

Cadmium Cd

Calcium Ca

Carbon C

Chlorine Cl

Chromium Cr

Cobalt Co

Copper Cu

Fluorine F

Gold Au

Helium He

Hydrogen H

Iodine I

Iron Fe

Lead Pb

Lithium Li

Magnesium Mg

Manganese Mn

Mercury Hg

Nickel Ni

Nitrogen N

Oxygen O

Phosphorus P

Potassium K

Platinum Pt

Silicon Si

Silver Ag

Sodium Na

Strontium Sr

Sulphur S

Tin Sn

Zinc Zn

APPENDIX T THE COMMON NAMES OF SOME CHEMICALS

Common Name Chemical Name

Alum Sulphate of ammonium, or potassium, etc.

Aqua fortis Nitric acid

Aqua regia Concentrated nitric and hydrochloric acid mixed.

Baking soda Sodium carbonate

Calomel Mercurious chloride

Carbolic acid Phenol

Caustic potash Potassium hydroxide

Caustic soda Sodium hydroxide

Chalk Calcium carbonate

Copperas Ferrous sulphate

Corrosive sublimate Mercuric chloride

Cream of tartar Potassium bitartrate

Epsom salts Magnesium sulphate

Fire damp Methane

Fool’s gold Iron pyrites

Glauber’s salt Sodium sulphate

Grape sugar Glucose; a carbohydrate

Hartshorn Aqueous solution of ammonia

Jeweler’s putty Tin oxide

Laughing gas Nitrous oxide

Lime Calcium oxide

Lunar caustic Silver nitrate

Mosaic gold Tin bisulphide

Muriatic acid Hydrochloric acid

Monsel’s salts Basic ferric sulphate

Plaster of Paris Calcium sulphate

Realgar Red arsenic sulphide

Red lead Lead oxide

Rochelle salt Sodium potassium tartrate

Royal water See Aqua regia

Sal ammoniac Ammonium chloride

Salt (common) Sodium chloride

Sal soda Sodium carbonate

Salt of tartar Potassium carbonate

Saltpeter Potassium nitrate

Salts of lemon Oxalic acid

Slacked lime Calcium hydrate

Soda Sodium carbonate

Spirits of salt Hydrochloric acid

Sugar of lead Lead acetate

Sugar of milk Lactose

Tartar emetic Potassium antimonious tartrate

Verdigris Copper acetate

Vermilion Mercuric sulphide

Vinegar Dilute acetic acid

Vitriol, blue Copper sulphate

Vitriol, green Ferrous sulphate

Vitriol, oil of Sulphuric acid

Vitriol, white Zinc sulphate

Volatile alkali Ammonia

Washing soda Sodium carbonate

White lead Lead carbonate

Zinc white Zinc sulfid

APPENDIX U THE FOUR CHIEF THERMOMETRIC SCALES

Fig. 130. The four chief thermometric scales: réaumur, absolute, fahrenheit and centigrade

There are four different thermometer scales used for measuring temperature and these are (1) the Fahrenheit scale which is widely used for all ordinary purposes; (2) the Centigrade which is the standard scale used for scientific work since it is based on the decimal system; (3) the Réaumur scale which is largely used in Germany, and (4) the absolute scale which is reckoned from absolute zero, that is the point at which there is absolutely no heat. It is about 461 degrees Fahr., 274 degrees centigrade, and 219 degrees Réaumur below the zero of these scales.

SOME WORDS AND TERMS USED IN THIS BOOK

Accelerate.—To hurry or speed up the usual slow state of events.

Actuate.—(1) To put into action. (2) Means by which anything is started to move. (See Operate).

Adhesion.—A force which makes certain bodies stick together.

Aërial Wire.—An elevated wire used to send out and to receive electric waves for wireless telegraphy and wireless telephony.

Affidavit.—A sworn statement made before a notary public or other legal authority.

Agent.—(1) A canvasser. (2) One who acts as a salesman or in any capacity for another.

Amend.—To change or correct, as to amend a claim in a patent.

Analysis.—See Chemical decomposition.

Arbor.—An axle, spindle, shaft or mandrel.

Archives.—A place in which official papers are kept and held secret.

Arlington wireless station.—A high powered wireless station at Arlington, Va., across the river from Washington, D. C.

Assignment.—To transfer to another a right or interest.

Attest.—To witness or to sign an oath that a thing is true.

Automatic.—A machine which performs certain operations of its own accord.

Aviation.—The art of flying.

Axis.—An imaginary line on or around which a body turns. (Plural Axes.)

Basic principle.—The first source or cause of a thing.

Biologist.—One who knows something about the science of life and living things.

Broker.—One who acts as an agent to negotiate purchases and make sales on a commission, as a stock-broker, coffee-broker, etc.

Capital.—Wealth that is used in or can be had for business.

Capital Stock.—The shares of a company that are sold to furnish funds with which to transact business.

Capitalize.—To fix a value on the stock of a company.

Case.—An application pending in the patent office.

Cause.—A suit or action over patent rights which is conducted in a court.

Certified copy.—A paper or a copy of a paper that has been sworn to before a notary to prove it to be the original or an exact copy of the original.

Chemical Combination.—(1) The atomic union of chemicals. (2) A compound of chemical elements.

Chemical Decomposition.—The separation of a compound with its original elements.

Circularize.—To send out circulars to a list of names.

Cite.—To quote a reference to an authority.

Citation.—An article or patent quoted by a patent examiner as a basis for the rejection of a patent application or of a claim.

Claim.—The last part of a patent specification in which the inventor clearly and specifically sets forth what his invention consists of and what he demands to have protected by a patent.

Claim, Broad.—(1) A broad claim is one in which the inventor claims everything in sight and usually more than he is entitled to. (2) It is easy to write a broad claim but hard to get it allowed.

Claim, Narrow.—(1) A narrow, or limited claim is one in which a patent attorney puts in so many elements or parts that the combination is bound to be patentable. (2) Such a claim has no value because it is easy for another to change an element or a part when the combination no longer infringes. (3) The hardest thing that an inventor has to contend with is to get a claim written so that it will stand in court.

Coincide.—Exactly corresponding to or meeting.

Conceive.—To get an idea.

Commission Merchant.—A man who stands between the manufacturer and the wholesaler and who gets a percentage on the amount of goods that change hands.

Commissioner of Patents.—The head, front and center of the patent office.

Concentric Circles.—Circles drawn within circles and all of them having the same center.

Corporation.—(1) A company. (2) An imaginary person invented by law and formed of one or more real persons banded together to transact business.

Correspondent.—(1) An associate. (2) A lawyer that carries on his business with another lawyer at a distance.

Consumer.—The last buyer and the user of an article or a device.

Cross-section.—See Drawing, Cross-section.

Counsel.—A patent attorney who is qualified to prosecute patent cases in court.

Data.—Information that is known or may be had.

Deductive Proof.—That form of thought by which an idea used as a starting point is brought to a conclusion by known principles and facts. (See Inductive Discovery.) Inductive discovery is the raw idea and does not lead up to certainty, whereas deductive proof does.

Degree.—(1) One three hundred and sixtieth part of a circle. (2) The unit of angular measurement.

Detailed Drawing.—See Drawing, Detailed.

Device.—(1) An apparatus or an instrument, or a machine or any part of any of them. (2) Any scheme for producing a desired result.

Die.—A steel tool having a sharp edge for cutting out special designs in paper, metals, etc.

Directors.—Members of a company chosen to direct its business.

Disclose.—(1) To make known. (2) To give up the secret of your invention.

Display ad.—An advertisement in which larger type is used than for the reading matter of the paper.

Dividends.—Money resulting from profits and which are distributed among the shareholders.

Drawing, Free Hand.—Pictures drawn without measurements or the aid of instruments.

Drawing, Working.—A drawing of a part, device or machine made to scale so that a mechanic can work from it.

Drawing, Cross Section.—A drawing of an object as though it had been cut in two in order to show its inside construction.

Drawing, Detail.—A drawing of any part of a device or a machine made large enough to show everything no matter how small.

Drawing, Perspective.—A drawing of a solid object on a flat surface so that it seems to stand out in space like the object itself.

Drawing, Isometric perspective.—See Isometric Perspective.

Du Ponts.—A firm at Wilmington, Delaware, who manufactures gun-powder and other explosives.

Efficient.—That which works the best with the greatest economy.

Element.—(1) A chemical element is a form of matter which cannot be decomposed. (2) A mechanical element is a single part of a device or a machine.

Electrolytic.—The decomposition of a chemical compound by an electric current.

Electroplating.—Depositing one metal on another metal by an electric current.

Electrotype.—A duplicate of type or cuts for printing, the body of which is of type-metal and the face of copper which has been deposited by an electric current.

Electrolytic.—Decomposition of a substance, or a solution by means of an electric current.

Electrolysis.—About the same as electrolytic.

Elementary.—Simple; primary.

Electro-Chemistry.—Chemistry in which electricity is used.

Engine lathe.—A large and accurate screw cutting lathe fitted with all known attachments.

Entering Edge.—The front edge of the main plane of an aeroplane.

Ether.—A substance filling all space and in, by and through which light, electricity and magnetism acts and travels.

Evidence of conception.—A signed and sealed statement made at the time or shortly after you get the big idea which will serve as proof of the earliest time you thought of it.

Excerpt.—A part, or an extract of an article.

Expert.—One who is trained or is skilful, due to learning and practice.

Experiment.—(1) To find out an effect, or the cause of it by trials and tests. (2) To work out a process for the purpose of developing an idea. (3) To show the effect of some previous discovery or invention.

Files.—Patents that are arranged systematically for easy reference.

Fixture.—See Jig.

Free-hand Drawing.—See Drawing, Free-hand.

Full paid.—Stock that has been paid for either in cash or by a patented invention.

High Frequency Oscillations.—(1) Electric oscillations. (2) Electric currents which alternate in direction 100,000 or more a second.

Idea, Raw.—The first idea that comes into the mind as a basis for an invention.

Improvement.—(1) Adding a new element or part to a composition, device or a machine. (2) An improvement constitutes an invention and can be patented.

Impulse.—A turbine wheel turned by steam forced against its blades.

Initiative.—The first step or action.

Indicate.—To point out. To show how a thing is done.

Inductive Discovery.—(1) The raw, or original idea that results from the mind process. It precedes deductive proof.

Inherent stability.—A natural tendency of a body to remain balanced, or when upset to right itself.

Isometric.—Of equal measure or scale.

Isometric Perspective.—Three sets of lines of equal measure, that is 120 degrees apart which represent the three dimensions of space.

Isometric Cross-section paper.—Paper ruled with lines of equal measure for making isometric perspective drawings.

Jig.—A tool, or fixture used as a guide for cutting tools where duplicate parts are made by a machine.

Jobber.—A man who buys in large quantities for the manufacturer and sells them to wholesalers or retailers.

Key.—A tapering wedge for fastening the collar of a wheel on a part of a shaft.

Litigation.—Law suits.

Low Voltage Currents.—(1) Currents having a pressure up to 500 volts. (2) Ordinary battery and lighting currents are low voltage.

Machine Design.—The scientific designing of machines.

Math.—Abbreviation for mathematics.

Maxims, Hiram and Hudson.—Inventors of high explosives, machine guns and other things that make for peace in times of war, and make for war in times of peace.

Mechanical Movement.—(1) The simplest form of a machine. (2) A combination of two or more of the mechanical powers.

Memorandum.—A written outline of an agreement, or a contract.

Micawber.—A character in Dickens’ David Copperfield. He was never able to get down to anything but was always waiting for something to turn up.

Model.—(1) An object or a device made to represent an apparatus or a machine. (2) A device made to show how an apparatus or a machine works. (3) Scale models are smaller than the machines they represent and may be built either to show how the finished apparatus will appear or they may be actual working models.

Monopoly.—The sole right to make, use and sell an invention or the product of an invention.

Notary Public.—A commissioned official who holds a seal of his office and who certifies papers, etc.

Oath.—A sworn statement of the truth.

Operate.—(1) To put into motion. (2) To do mechanical work. (See Actuate.)

Ozone.—A colorless gas formed by discharging electricity through the air or oxygen.

Paper patent.—A patent granted by the patent office for an idea that has never been worked out in practice.

Part.—A small portion of a device or a machine.

Par value.—The full, or face value.

Patent attorney.—A lawyer who makes patent law his business or ought to.

Patent Expert.—One who is specially trained in an art or a science which enables him to give expert testimony in patent causes.

Patent Office.—(1) The building in which the patent business of the government is transacted. (2) The office conducted by the government for handling of its patent business. (3) The patent office of the U. S. is one of the bureaus of the Department of the Interior and it is under the direction of a commissioner of patents.

Patent Examiner.—One who examines and passes on patents in the patent office.

Patentee.—The one to whom a patent is granted.

Periphery.—(1) The circumference of a circle. (2) The outer surface of a wheel.

Perspective Drawing.—See Drawing, Perspective.

Perspective, Isometric.—See Isometric Perspective.

Philosophy.—(1) The science of all natural laws. (2) The laws, causes and principles on which facts can be explained. (See Psychology.)

Precision.—(1) The state of being very accurate. (2) Said of any instrument or machine which works with exactness.

Principle.—A truth or cause.

Priority.—Being first.

Protractor.—An instrument for laying off and measuring angles by degrees.

Prosecute.—To follow up until a conclusion is reached.

Pro Rata.—In proportion.

Psychological moment.—The exact time to impress the mind in the best way.

Psychology.—(1) A branch of philosophy. (2) The science of the mind and its operations.

Ramifications.—Subdivisions of a subject or branches of a thing.

Reaction.—A turbine wheel turned by steam forced from it against the air.

Rectify.—(1) To make right whatever is wrong. (2) To make a direct current of an alternating current.

Rectangle.—A four sided plane with right angle corners.

Reject.—To refuse to accept, as to reject a claim in a patent.

Retainer.—The advance fee paid to an attorney.

Retailer.—A man who buys in small quantities and sells piecemeal to consumers.

Royalty.—A share of the profits paid to the owner of a patented article or a device by those whom he allows to make or use it.

Scale.—A piece of wood, metal or other material with graduated lines on it and used for measuring.

Securities.—Property of any kind which has enough value to keep the credit good.

Semi-circle.—(1) Half of a circle. (2) A segment of a circle equal to 180 degrees.

Shares.—(1) The equal parts of the capital stock of a company. (2) The shares are represented by certificates.

Shareholder.—An owner of the shares of stock of a company.

Shop-right license.—A legal permit given to the owner of a shop to make and sell a patented article or device.

Sketch.—A crude picture.

Standardize.—To make a device or a machine to conform to a certain type.

Stockholder.—An owner of the shares of the stock in a company.

Stock.—(1) The shares of a company which represent its capital. (2) Goods traded in for a profit. (3) The raw materials used for manufacturing purposes. (4) The manufactured goods that are held in reserve.

St. Elmo’s Fire.—An electric glow which is often seen at the end of a spar of a ship at night.

Synthesis.—To combine chemical elements to form a compound.

Synthetic.—A chemically prepared substance which is exactly like that found in nature, as synthetic camphor, synthetic sapphires, etc.

Technical Expert.—See Patent expert.

Transfer of Energy.—Changing the energy of one body to another body.

Transformation of Energy.—Changing the form of energy, as from electricity to magnetism, or from heat to light.

Transactions, or Proceedings.—The published reports of scientific and other societies.

Treasury stock.—The shares that belong to the company and which are used to provide it with working capital.

Trustees.—About the same thing as directors.

Tungsten.—A steel gray metallic element.

Tyro.—A beginner.

Useful art.—Anything which requires ingenuity to fashion, and which can be used for some good purpose.

Valid.—(1) That which holds good. (2) A patent that is founded on fact and in law.

Who’s Who.—A red book of noted men and women living in the United States.

Wholesaler.—One who buys and sells in large quantities.

Wing.—The main or supporting plane of an aeroplane.

Working Drawing.—See Drawing, Working.