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URREY, TYPE TWO has ample power for rough roads and hills; has throttle (speed regulator) attached to steering wheel-one

hand can manage both; automatic spark governor; cooling system that makes pumps and fans unnecessary; powerful brakes long wheel base; large wheels and tires; can. opy top; water-proof side curtains; plate-glass swinging front; and other marked provis. jons for comfort, safety and reliability $2000, complete with lamps, tools, etc. Other models $750, $850 $1350, $ 3000 THOMAS B. JEFFERY & COMPANY Main Office and Factory, Kenosha, Wisconsin Branches, Boston, Chicago, Philadelphia New York Agency,134 West Thirty-eighth Street Representatives in all other leading cities.

Mention The Technical World,

For Experts

CONSULTING DEPARTMENT-(Continued) ure in pounds per square inch due to the head; S, the allowable working stress (12,000 pounds); E, the efficiency of the

joint (-7, assumed). Substituting the Engineers, Architects, Draughts value of P (7.8) for the first section, we men—Students or Experts

have should get acquainted with the

96 X 7.8

.0445 inch.

2x 12,000 X.7 resources of supply for all drawing

In a similar manner we find the value and sketching materials offered

of t for the lower section to be .136 by this house.


The above calculations allow for the static Our catalogue contains the facts

pressure alone. and the figures about it all. Our

When the water is passing through the goods contain the quality that real

tube, there will be certain dynamic experts appreciate. We send the forces, caused by change in direction at book to anybody who is interested

the bend. This will necessitate bracing in the goods.

the pipe at the bend mentioned, and, of course, it should be properly supported

throughout its length. Devoe & Raynolds Company

176 Randolph Street, Chicago Fulton and William Sts., New York

Cadmium Test 1214 Grand Ave., Kansas City, Mo.

Question: Kindly inform me of the proper test of storage batteries by means of the cadmium stick, and how to conduct such test.R. G. H.

Answer: The voltage of a battery does not always indicate the state of charge. One method of finding the amount of charge in a storage battery is called the “Cadmium Test. ratus for making this test may consist of a small piece of cadmium, 58 inch by 5. inch by 1-32 inch, mounted so that a glass tube contains the conducting wire, wax being used to protect the soldered joint of copper and cadmium. With normal conditions of cell when fully charged and on open circuit, the difference of potential between the cadmium piece and

the positive plate is approximately 2.5 of the most practical and in

volts, which is sufficient. The cadmium structive articles, regarding the

test is usually made at the center of the designing, building and oper

ce!l, giving uniform current distribution. ating of motor-driven vessels,

The test will give readings, some of that can be written — ; price

which are below 2.5 volts, if hydrometer $2.00 a year domestic

test, temperature, and charge data show 2.50 a year foreign

that the cell is not fully charged; but if Sample copy free

the hydrometer, temperature, and other

data show the charge to be complete, and MARINE ENGINEERING

the cadmium gives .I volt or more below

2.5 volts, the defective plate is deter17 Battery Place . . New York, U. S. A. mined by individual cadmium readings.

When the battery is discharged-that is, Mention The Technical World.


The appa

Averages 700 Pages with 700 Illustrations


Main Building, Armour lostitute of Technology

Preparation for College

CONSULTING DEPARTMENT-(Continued) to 1.8 volts-the voltage between the cadmium test piece and the positive plate should be about 2.05; and between the cadmium and the negative plate, .25. The cadmium should be positive to both elements. The voltage of the cell equals 2.05 .25 (= 1.8). If we have a cell in which the conditions tend to show full charge but the potential difference is low, a cadmium test is made. Whichever plate shows a falling off from the normal reading, that plate is the defective one.

The following precautions should be taken in making this test: It is advisable to have the cadmium plate wet before the test is made. The cadmium plate should be shaken occasionally to free it from any bubbles of gas that may form on the surface. The plate should be washed with water every time it is taken from the cell. The simplest way to accomplish this is to keep the cadmium tester in a beaker of distilled water. The cadmium should be free from impurities or foreign matter of any kind.

The surface of the metal should not be scraped bright, but it should be allowed to oxidize slightly. There is a difference of potential between cadmium and cadmium oxide; and, as the bright surface oxidizes quickly, it would be practically impossible to keep the surface bright. Care should be taken that the cadmium does not come in contact with plates or connections. This may be prevented by covering the cadmium with rubber, and perforating the covering with numerous small holes.


Instruction under the direction of the regular teachers in a resident engineering college.

Lessons prepared especially for home study by teachers of acknowledged standing.

The full College Preparatory Course covers the entrance requirements of such a college as ARMOUR INSTITUTE OF TECHNOLOGY, and students satisfactorily completing this course are admitted to the college of engineering of that institution without further examination in the subjects taken.

An unusual opportunity for young men of limit. ed means to prepare for entrance to an engineer. ing college without leaving home or interfering with their regular work.

CHILDREN AT HOME as long as pos-
sible before sending them to college will
find these courses of great value. There
is no breaking of home ties, and the
student not only has many of the ad-
vantages of a private tutor but also the
sympathy and encouragement of his

parents. This is an excellent opportunity for teachers and others to take up engineering studies in their own homes and at their own convenience under the guidance of resident school teachers.

In addition to the College Preparatory Course instruction is also offered in

Mathematics (A hmetic, Algebra, Geom-
etry and Trigonometry), Electrical,
Mechanical, Steam, Sanitary and Civil
Engineering: Architecture, Mechanical
Drawing, Telegraphy, Telephony and
the manufacture of Textiles (Spinning,

Weaving and Knitting). 200 page illustrated Bulletin, giving full information as to courses, teachers, methods of study. etc., may be had upon request.

Hardening of Steel Tools Question: Is it good practice to use acid baths for hardening steel tools? If not, what is a good formula?-E. S. K.

Answer: With acid baths, excellent results, so far as the hardened surface is concerned, can be obtained. Their use is not advocated, however, as the after effect is to rot the steel. A bath that gives excellent results is: Six quarts of soft water, one ounce of corrosive sublimate, and two handfuls of common table salt. Use when dissolved. Another formula for making tools tough and hard is: 12 teacupful salt, 1/2 ounce saltpeter, i teaspoonful pulverized alum, and i gallon soft water.

American School of Correspondence

Armour Institute of Technology


Mention The Technical World, Feb.

Mention The Technical World.

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We also make John T. McCutcheon's "Bird Center Etiquette"


HOME GAME CO. 92 Dearborn Street



This Vest Pocket Electric Search Light

Every One Guaranteed

A New Profession



Beware of Cheap Imitations But a useful, praetseal, durable and convenient article for everyone. Fits nicely in vest pocket. Handy for Farmers to take to barn at night.-No danger of fire-can't blow out-always ready-simply press the button and you have instant light. Invaluable for PHYSICIANS, WATCHMEN, PLUMBERS, CLERGYMEN, MINERS, RAILROAD MEN, BANKERS, HUNTERS. TRAVELERS, ETC. Women folks find it handy about the honse for cellar, dark corners, etc.--in fact, everywhere. bright, safe light is wanted. No heat, matehes, chemicals. SAFE-a child can operate it. No wire, smoke, smell or dirt. Nothing to break-it lasts for years. New Batteries 30e, Bulbs, 35e, each, postpaid. Can change instantly. Once you bave it, you would never be without it. Send today for free electrical catalog - it shows a large line of USEFUL electrical novelties for all purposes. AGENTS make big money selling our goods. Write for terms. Sutcliffe & Co., 518 S. Main St., Fall River, Mass.

ARE y mum interested in

, Water Power Electric Plants, complete, or parts or castings! Why not build one using our finished parts and try your own winding. Noextrasorfurther expense. Perhaps a good water motor is what you are looking for; better investigate our de

signs and sizes 1-16 to 15 H. P. May be you are in the market for Marine, Auto or Bicycle Gasoline Motors or castings, get our prices. State what you migbt want and get benefit of lowest quotation, enclosing 4 cents for catalogue.

Good, live, hustling representatives wanted. C. S. PIPER & Co. 4352 Cottage Grove Avenue,


OME-MAKING, as now taught in some of

the colleges, ranks as a profession as truly as

any occupation—it is greatest in numbers and greatest in its effect on the individual and on society. “As a man's home is, such is his life.”

The basis of this new profession is Hygiene all that makes for health-personal hygiene, healthful surroundings, healthful food, cooking, clothing, care of the sick, the right care of children, etc. Then comes the Economy of Living-true economy of time, effort and expenditure, system of work, household conveniences, the division of income, buying, household accounting, etc. Then, the Simple Life— living in a simple, rational, artistic way; and-most important - the Children, whose health, character and final success in life is so largely determined by the home care and training.

Every woman who would like to have something better than tradition, hear-say, and scraps of information as guide in her life work will be interested in the Announcement of the American School of Household Economics which tells of the authoritative correspondence instruction and advice given by prominent teachers of the “profession of homemaking." This attractive, illustrated 48-page book will be mailed free to any one sending a postcard addressed A. S. H. E. 3311 Armour Avenue, Chicago, Ill.

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Mention The Technical World.

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