CH. VIII] PREPARATION OF LANTERN SLIDES 207 



those not especially skillful, it is probably better to draw the sketch 

 first and then trace the sketch on glass as follows: Place the 

 lp,ntern-slide glass on the drawing, varnish side up, and arrange it 

 as desired. Select very thin glass for this, so that the drawing sur- 

 face will be near the picture to be traced. Now with a pen or 

 brush trace the outlines. One can also use colored inks if desired. 



321. Guide for table making and for writing. For making 

 lantern-slide tables or written matter direct on the slide it is best 

 for most workers to have a guide which shall show the maximum 

 size which can be projected (fig. 115). If one has no special guide, 

 cross-section paper or catalogue cards will serve well. 



To hold the glass in position while writing or making diagrams, 

 thumb tacks at the corners are efficient (fig. 115). 



322. Ink and pen to use on unvarnished glass. For tem- 

 porary use, as in reporting games, etc., the glass is cleaned and 

 then the fingers rubbed over it. Now with a ball-pointed pen one 

 can write upon the glass. The lines will be coarse, but that will 

 not matter. One can write with an ordinary pen also, but not so 

 surely as with a ball-pointed pen ( 322a). 



The ink can be of almost any kind. The black India ink gives 

 the sharpest images. 



A special ink called "glassine" has recently been put on the 

 market. It is in six colors, white, black, red, green, blue and violet. 

 The ink is thick and with it one can write on untreated glass with 

 any pen, although a ball-pointed pen is here also an advantage 

 ( 322b). The ink is easily washed off with water so that the same 

 glass slide can be used over and over. 



322a. The writers are indebted to Dr. E. M. Chamot for the suggestion 

 to use the ball-pointed pens on the unvarnished glass, also the advantage of 

 rubbing the fingers or palm over the cleaned glass to prevent the ink from 

 spreading. 



According to Lewis Wright, p. 412, one can write on glass well if the glass is 

 licked, and the thin coating of saliva so spread upon the glass is allowed to dry. 

 The ink will not spread, and the saliva-coated glass takes the pen well. 



322b. "Glassine announcement slide ink." This ink is made by the 

 Thaddeus Davids Co., 127 William St., N. Y., and is supplied in I oz. (30 cc.) 

 bottles, the full set of six colors costing $1.00. See the Moving Picture World, 

 March, 1914. 



