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Xmas Tree Outfit


THIS outfit consists of a number of feet of flexible cord with a regular attaching plug at one end, and branch festoons, each having eight miniature pendant sockets wired thereon. With the outfit is supplied the neccessary number of Miniature Decorative Lamps, plain and in colors.

(f To arrange the lighting decoration it is necessary only to screw the attaching plug into the nearest regular lamp socket, drape the wires over the tree, screw the little lamps into the sockets, and the decoration is complete.

*J The outfit is simple, flexible, thoroughly constructed and perfectly safe.

fl The first cost is low, considering that the Miniature Lamps

are included, and an outfit once purchased will last for years and

can be used repeatedly with little trouble and no additional


•3 The outfits will be supplied for eight lamps and multiples of

eight; that is 8, 16, 24. etc., lamps. Orders should specify

voltage of circuit and type of regular lamp socket used.

The following is a list of the sizes supplied:

Eight Light Outfit $5.00

Sixteen Light Outfit 8.50

Twenty-four Light Outfit 12.00

Thirty-two Light Outfit 15.00

Extra festoons (ready for connection) consisting of eight

sockets with extra lamps for increasing size of outfit 4.00 The Twenty-four Light Outfit is the standard size.

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Three-Way Switch Connections

Question: Enclosed herewith find two pen sketches. In regard to sketch No. I, I wish to know how lights A and B can be arranged on a three-way switch, so that when light A is

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Th/ve-Way Switch

Fig. 1.

on, light B will be off, and vice versai. e., completing a circuit on one light and breaking the circuit on the other by a single turn of the switch. In sketch No. 2, I wish to know if this is the proper method for connecting up three-way switches.—/?. W. C.

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Three-Way Switch
Fig. 2.

Answer: Referring to sketch No. 1, the full lines represent the part which you show. The sketch has been completed with dotted lines indicating the proper method of wiring to obtain the desired result. One turn of the switch will throw off the light which is burning, and throw on the other, in every case. The wiring shown in sketch No. 2 is entirely correct for the three-way switch as it is used for the purpose of controlling a light from two separate points. The light can be turned on or off from either of the two three-way switches shown.

Probable M. E. P. of Steam Engines

Question: Please explain how to find the Mean Effective Pressure of a 6 x 12 steam engine making 250 revolutions per minute, the boiler pressure being 80 pounds by gauge.—

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The Penberthy
Automatic Injector

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Low Water Alarm

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0, Off on Catalogue Prices

"Hereafter we will give to the public direct in fall all teachers' and dealers' discounts on violins, guitars, mandolins, and other stringed instruments. Our standard Lewis Orchestra No. 1 violin {worth easily $25 to $30 among dealers; listed in our catalogue for years at $21; now $10.50 net direct to you). The famous Lewis Stradivarius model $65 violin for £32.50. Other values for from $.'* 50 to $125 and upward. We i are the largest and oldest exclusive stringed 'instrument house in the U. S., and import direct from our own worKshops in Eisleben, Germany, and Padua. Italy. Ten days' free trial of our instrument. Write for catalogue.


Dept. T. 220 Wabash Avenue. Chicago, 111. OUR SPECIALTY: Strings for the professional trade.

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Answer: Your question cannot be given an absolute answer, for the reason that the M. E. P. depends on other factors than those which you have given. In other words, it would be necessary to know the cut-off, the back pressure, and type of engine. Making certain assumptions, we can give you an approximate answer. If the cut-off is %, then the ratio of expansion is 4, neglecting clearance. Assuming the back pressure to be 3 pounds gauge, then the M. E. P. can be found by the formula

M. E. P. = P1+h>pR'ogR_/,

in which

P = Absolute initial pressure.

R = Ratio of expansion.

/> = Back pressure (absolute).

Since the gauge pressure is 80 pounds, P is 80 + 14.7 (= 94.7) pounds; R we have assumed to be 4; and p is 3 + 14.7 (= 17.7). Substituting in the formula, we have:

M. E. P. = 94.7 l+J-386? _ 177 4

= 56.5—17.7 = 38.8 pounds.

We have made no allowances for losses due to compression, clearance, condensation, wire drawing, etc. To allow for these in a plain slide-valve engine, it is customary to multiply this theoretical M. E. P. by the factor .8, which will give us for the probable M. E. P., 38.8 x .8 (= 31.04) pounds.

In the formula used above, you will find the term "hyp. log. R.'' We are to substitute for this term the hyperbolic logarithm, or, as it is sometimes called, the Napierian logarithm of the factor R. These logarithms will be found in almost any engineer's handbook.

Exhausting Under Water

Question: Is it possible for two-cycle gas engines to exhaust under water without seriously reducing the H. P. of the engines?— B. O.

Answer: This is frequently done without loss of H. P. by extending the terminal under water, with a small vent above the water. The vent prevents the water from drawing back to the muffler when the motor stops.

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C. Model "H." Capacity four passengers. Speed up to twenty-
five miles an hour. $850. Equipped with tools, oilers, pump,
repair kit, brass oil side lamps and brass horn.

C In this model the speed is regulated by the trottle attached to
the steering wheel, requiring only one hand to steer and control.
The ignition is timed automatically by a governor in exact require-
ment to the speed of the engine. Brakes both on transmission and
rear wheels. Power sufficient for grades up to forty per cent.

C Made in our own factory where the facilities are so complete that they
involve the making of bolts and nuts even. These exactly fit the spanner
wrenches which go with our vehicles.

C. The tonneau of Model " H" can be readily removed and the
vehicle converted into a run-about, Model "G", and at slight
expense delivery wagon top can be added. C. Send for THE
RAMBLERj cTWAGAZINE and other printed matter.

Thomas B. Jeffery" C& Company"


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