98 



Popular Science Monthly 



held in place by the brass edgings at the 

 side of the contrivance. 



It will be noted from the illustrations 

 that the vertical lines on the 

 glass are numbered serially 

 from left to right. The hori- 

 zontal ones are divided into 

 two sets, each designated by 

 similar groups of letters. The 

 user of the device merely 

 slides the metal plates around 

 (using the handles projecting 

 beyond the glass at each end) 

 until, say, the upper left-hand 

 corner of the good bill rests 

 beneath the point A-i of the 

 cross-hatching on the glass, 

 and the remainder of the bill 

 is correspondingly lined up 

 and square with the rest of the 

 cross-hatching. Similarly he 

 brings the upper left-hand 

 corner of the bad bill to rest 

 beneath the point A of the 

 lower section of the ruling — afterward like- 

 wise bringing the other parts of the bill into 

 agreement with the rest of the squares. 



All of this has the effect of placing a good 

 bill and a bad bill squarely before an ob- 

 server, and because of the cross-hatching on 

 the glass, of dividing up the surface of each 

 bill into similar squares, each of which 

 may be compared in detail. As is readily 

 evident, if the bad bill is distorted in any 

 particular, the defect will immediately 

 become apparent under such close scrutiny 

 as this sectionalizing into small squares 

 makes possible. 



The most valuable feature about the de- 

 vice is the fact that the two oblong blotter- 

 faced metal plates and their accompanying 

 good and bad bills, may individually be 

 moved up and down and round 

 about by means of the handles 

 at each side and a variety of 

 comparisons made, all 

 without disturbing the 

 glass itself in any way. 



The tests performed 

 usually consist in com- 

 paring the various orna- 

 ments on a bill for ac- 

 curacy of size and shape 

 — the moving around be- 

 ing a valuable feature, 

 since the ornaments do 

 not always happen to fall 

 completely within a set 

 of .squares. 



The various ornaments on the bills are compared for accuracy 

 of size and shape. The plates are moved around by means of 

 the handles at the sides to facilitate the comparisons 



Counterfeit coins are compared in the 

 same way as bills, only a finer screen is 

 necessary. Counterfeit money has to be 

 good indeed to pass the kind of a test this 

 machine can give it. 



O' 



Spring-brass wire, bent as here 

 shown, will convert any nib 

 into an automatic fountain pen 



Providing Your Pen with an 

 Automatic Fountain 

 F course every boy wants a fountain 

 pen. He will buy one the very first 

 chance he gets; but good fountain pens are 

 rather expensive for the purse that goes 

 with "knickers," and an unreliable one is 

 likely to prove such a disappointment that 

 it is worse than none at all. However, you 

 can add the advantages of a fountain-pen 

 to any ordinary pen-point by a new at- 

 tachment, made very simply of spring- 

 brass wire. The main part of 

 the attachment lies in two 

 small coils which are 

 fixed under the point of 

 the pen to hold the sur- 

 plus ink. These coil ends 

 join at the rear, while 

 those near the front of 

 the pen are turned up and 

 back to fit tightly against 

 the top of the pen. The 

 jaws so formed serve the 

 purpose of clasping the 

 attachment to the pen- 

 point and of uniformly 

 feeding the ink to the 

 point as it is needed. 



