Popular Science Monthly 



463 



is simple, efficient, inexpensive and small. 

 A small commercial house could, in some 

 cases, use the plan to advantage. The 

 outfit can be placed on the wall of the dark 

 room in an unused corner. Made in 



This method of development economizes in 

 chemicals, as a very small quantity is required 



approximately the dimensions shown, which 

 may be varied to suit the conditions, it will 

 accommodate from 10 to ioo ft. of film and 

 it will use less than I quart of developer per 

 ioo ft. of film. 



The film to be developed is wound around 

 the rollers as if it were a belt, with the 

 emulsion side out. The upper bracket 

 carrying one of the multiple rollers is 

 adjustable for different lengths of film, so 

 that the single idler will serve to compensate 

 for the slight variation in the film length 

 during developing and drying. When ad- 

 justed properly the ends of the film are 

 spliced together, thus making a continuous 

 belt. The upper set of rollers consists of a 

 flanged stick on a shaft equipped with a 

 grooved pulley so arranged that it can be 

 belted to a motor or, in the absence of a 

 motor, to another wheel placed con- 

 veniently and fixed in a way to enable the 

 operator to run the apparatus by hand. 



The developing pan or tray is preferably 

 an enameled baking pan which can be 

 partially filled with either developer, water 

 or hypo solution and raised underneath the 

 bottom set of rollers so as to immerse the 

 running film into the several liquids as 

 desired. The film can be stopped and 

 examined at any time and the solutions 

 changed in a few moments, especially if the 



operator has a pan for each solution. 

 After development, fixing and washing, the 

 film may be quickly dried by running it 

 over the rollers while the air from a fan is 

 turned on it, provided the room is free from 

 dust, which is essential for all the work. 



In setting the apparatus for any length of 

 film it can be marked on a scale for future 

 use, or by the use of a tape line the device 

 can be calibrated and marked so the 

 rollers may be set at once and properly for 

 any length of film. The entire apparatus 

 should be painted with paraffin dissolved in 

 gasoline to prevent the wood from wetting 

 and swelling, and to prevent the absorption 

 of fluids by the unprotected parts of the 

 frame. — T. B. Lambert. 



A driver to turn 

 studs in aluminum 



A Driver to Turn Studs in 

 Aluminum Castings 



METAL workers who attempt to put 

 studs into aluminum castings usually 

 do the job with tools not intended for the 

 work. A very handy tool may be made for 

 this work, as shown in the illustration. It 

 will be necessary to 

 have a set of these 

 tools, one for 

 each size stud 

 used. The stud 

 is screwed into the 

 tool as far as it is 

 necessary ; then the 

 center piece is screwed 

 down tight upon it to 

 hold the stud in place. 

 The stud may be 

 driven tight into the 

 casting and the center piece loosened ; then 

 the tool may be turned off from the stud 

 with perfect ease, leaving the stud set. The 

 shank of the tool is made of hexagon stock 

 and the center piece of ^8-in. round ma- 

 chine steel. — Theron L. Winchip. 



A Lasting Paint for Covering a 

 Heated Surface 



A GOOD black, heat-resisting paint for 

 the front of a locomotive, or other 

 place subject to heat, can be made in the 

 following manner: Shave 6 pounds of 

 brown soap and melt it in water, then add 

 more water to make it up to 12 gal. Mix in 

 18 gal. of Japan oil, then stir in 80 lb. of the 

 best graphite. This will make about 35 

 gal. of paint. Stir the mass well and apply 

 while the object is not too hot. 



