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TURREY, TYPE TWO has | ample power for rough roads and

|hills; has throttle (speed regulator) azul attached to steering wheel-one

a hand can manage both; automatic spark governor; cooling system that makes pumps and fans unnecessary; powerful brakes long wheel base; large wheels and tires; çan. opy top; water-proof side curtains; plate-glass swinging front; and other marked provis. ions 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 Expe rts

Engineers, Architects, Draughtsmen-Students or Expertsshould get acquainted with the resources of supply for all drawing and sketching materials offered by this house.

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 value of P (7.8) for the first section, we have

96X7.8 t = 2x12,000 X.7 = .0445 inch. In a similar manner we find the value of t for the lower section to be .136 inch.

The above calculations allow for the static pressure alone.

When the water is passing through the tube, there will be certain dynamic forces, caused by change in direction at the bend. This will necessitate bracing the pipe at the bend mentioned, and, of course, it should be properly supported throughout its length.

Our catalogue contains the facts and the figures about it all. Our goods contain the quality that real experts appreciate. We send the book to anybody who is interested in the goods.

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.” The apparatus for making this test may consist of a small piece of cadmium, 5.8 inch by 55 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.


Averages 700 Pages with 700 Illustrations

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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. Main Building, Armour Institute of Technology

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 sur

face. The plate should be washed with BY MAIL

water every time it is taken from the

cell. The simplest way to accomplish Instruction under the direction of the regular this is to keep the cadmium tester in a teachers in a resident engineering college. Lessons prepared especially for home study by

beaker of distilled water. The cadmium teachers of acknowledged standing.

should be free from impurities or foreign The full College Preparatory Course covers the en

matter of any kind. trance requirements of such a college as ARMOUR

The surface of the metal should not be INSTITUTE OF TECHNOLOGY, and students satisfactorily completing this course are admitted scraped bright, but it should be allowed to the college of engineering of that institution

to oxidize slightly. There is a difference without further examination in the subjects taken. An unusual opportunity for young men of limit

of potential between cadmium and caded means to prepare for entrance to an engineer

mium oxide; and, as the bright surface ing college without leaving home or interfering

oxidizes quickly, it would be practically with their regular work.

impossible to keep the surface bright. PARENTS wishing to KEEP THEIR CHILDREN AT HOME as long as pos

Care should be taken that the cadmium sible before sending them to college will

does not come in contact with plates or find these courses of great value. There is no breaking of home ties, and the

connections. This may be prevented by student not only has many of the ad

covering the cadmium with rubber, and vantages of a private tutor but also the sympathy and encouragement of his

perforating the covering with numerous parents.

small holes. 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

Hardening of Steel Tools guidance of resident school teachers.

Question: Is it good practice to use acid In addition to the College Preparatory Course

baths for hardening steel tools? If not, what instruction is also offered in

is a good formula ?-E. S. K. Mathematics (Arithmetic, Algebra, Geometry and Trigonometry), Electrical,

Answer: With acid baths, excellent Mechanical, Steam, Sanitary and Civil

results, so far as the hardened surface is Engineering: Architecture. Mechanical Drawing, Telegraphy, Telephony and

concerned, can be obtained. Their use is the manufacture of Textiles (Spinning,

not advocated, however, as the after efWeaving and Knitting).

fect is to rot the steel. A bath that gives 200 page illustrated Bulletin, giving full infor

excellent results is: Six quarts of soft mation as to courses, teachers, methods of study. etc., may be had upon request.

water, one ounce of corrosive sublimate,

and two handfuls of common table salt. American School of Correspondence

Use when dissolved. Another formula

for making tools tough and hard is: 12 Armour Institute of Technology

teacupful salt, 1/2 ounce saltpeter, i teaCHICAGO, ILL., U.S.A.

spoonful pulverized alum, and i gallon =Mention The Technical World, Feb. =

soft water. Mention The Technical World.


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This Vest Pocket Electric Search Light Every One Guaranteed


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Beware of Cheap Imitations But a useful, practical, 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 a bright, safe light is wanted. No beat, matehes, chemicals. SAFE a child can operate it. So wire, smoke, smell or dirt. Nothing to break-it lasts for years, New Batteries, 30e, Bulbs, 35c, each, postpaid. Can change instantly. Once you bave it, you would never be without it. Send today for free eleetrical 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.

RE you interested in
Dynamos, Motors,

Water Power Electric
Plants, complete, or parts
or castings! Why not build
one using our finished parts
and try your own winding.
Noextras orfurther 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, . • CHICAGO, ILL.

LJOME-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 Hygieneall 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.

If your Subscription Expires with this issue or with the next, or if you are not a subscriber see the special announcement on pages VIII and IX in the front section of this issue. It will interest you.

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