932 



Papular Science Monthly 



ROUND 

 STEEL 



A Steel Boring Mill Tool-Holder 

 Requiring Little Material 



WITH the price of high speed tool steel 

 soaring, devices for the conservation 

 of this kind of material 

 are being sought. With 

 this thought foremost the 

 device for holding a bor- 

 ing mill tool, as illustrat- 

 ed, was developed and a 

 great saving in material 

 effected. The entire tool, 

 made of high speed steel, 

 will weigh about \Yi lb. 

 The piece of steel used in 

 the holder weighs about 

 4 oz. This holder can be 

 made in a variety of 

 shapes, and different tools 

 can be used. Pressure 

 exerted by the set-screw 

 on the round-pin holds 

 the tool in place. The 

 round pin is roughened or knurled on the end 

 to hold on the steel surface. — J. R. Minter. 



A Treadle for an Automobile 

 Foot Accelerator 



ON a great many cars the accelerator 

 consists of a plunger rod, with a metal 

 disk at the end, for the foot to rest upon. 

 As it is often 

 difficult to keep 

 the foot pres- 

 sure steady up- 

 on the button, a 

 constant in- 

 crease and de- 

 crease of speed 

 is the result. 



With this in 

 mind, I con- 

 structed a 

 treadle along the lines shown in the sketch, 

 which overcomes, to a great extent, the 

 uneven pressure, and also gives an easier 

 position for the foot. 



The under side of the treadle was chan- 

 neled so as to keep it always in place on 

 the button. The top surface was furnished 

 with corrugated rubber and the lower end 

 hinged to the car floor. As a result the 

 car ran much more smoothly and the leg 

 muscles were relieved from the constant 

 strain of adjusting the pressure upon the 

 accelerator. — L. B. Robbins. 



Treadle to ease the foot 

 on accelerator pedal 



An Improvement on the Old-Time 

 Back to Back Card Trick 



THIS trick originally consisted in read- 

 ing off the cards one by one as they 

 were shown to the audience without your 

 having had a chance, apparently, of seeing 

 them at all. The secret consists in placing 

 two halves of the pack back to back, so 

 that one half faces one way and the other 

 in an opposite position. Notice what the 

 face card is on one side and hold the pack 

 up so that the audience can see it. While 

 you are doing this you will have a chance 

 to notice the rear card, that is the card 

 facing toward yourself. As soon as you 

 have done this place the pack behind your 

 back or under the table and transfer the 

 rear card to the front of the pack, thus 

 bringing into view the one you have just 

 named and at the same time disclosing 

 the next card in the rear. On holding the 

 pack up to the audience you will be en- 

 abled to name the card next to appear. 

 It is needless to say that no one should be 

 allowed behind the performer while this 

 trick is in progress. 



The variation of this trick employs a 

 mirror in order to deceive the "knowing 

 ones" who are familiar with the older 

 method of working it. For this newer 

 method, the pack is not cut and put back 

 to back, but the cards all face in one 

 direction. Somewhere overhead a mirror 

 is placed where it will reflect the cards to 

 you, but in such a position that it will not 

 be seen by the spectators. As the cards are 

 reflected in this you will be able to read 

 them off without lowering the cards. Be 

 careful to hold the pack between your 

 eyes and the spectators so that the di- 

 rection of your glance is not detected. 



Newspaper as a Substitute for 

 Chalk Talk Lecturers 



CHALK talkers, lecturers and teachers 

 who use paper and crayons to show 

 diagrams, sketches, figures, etc., now find 

 the prices of large sheets a serious con- 

 sideration. Their outlay may be materially 

 reduced if they will use old newspapers that 

 have a comparatively even gray appearance 

 from a distance. Select the sheets that 

 have no dark or heavy cuts, headings and 

 the like, such as the "Help Wanted" pages, 

 and use the regular "chalk talker's" 

 crayons. The printing will not detract from 

 the drawing; in fact it can scarcely be 

 noticed by the audience. — A. B. Wagener. 



