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A Self-Rocking Developing-Tray 



A SIMPLE form of mechanical 

 rocker, which may be relied upon 

 to keep up a steady, gentle movement 

 for a long period without attention, is a 

 great convenience to the busy photo- 

 grapher. A flat, square board, rather 

 larger than the developing - tray, is 

 pivoted on the apex of a zinc triangle, as 

 shown in Fig. I. The zinc triangle is 

 easily made from a strip of sheet zinc 



FIG. I 



Popular Science Monthly 



The counterbalance swings under the 



table and the tray rocks easily and 



continuously without attention 



as long as the side of the board and bent 

 into the form of a V, with flanges for 

 attachment to the board. It should be 

 screwed along the exact center of the 

 under side. An alternative is to use a 

 triangularly-shaped piece of wood, IV^'^ 

 thick, nailed through from above. The 

 wood must, of course, be rather hard. 

 A piece of strong, flat iron, 3' or more 

 in length, must be fastened at one end 

 to the under side of the base, also in the 

 center, but at right angles to the pivot. 

 This is shown in Fig. II. 



With the board standing on the edge 

 of the table, the iron should be bent into 

 a curve reaching under the edge of the 

 table as illustrated. A weight of several 

 pounds is firmly secured to the free end 

 of the iron. This weight can be made 

 by casting ten or twelve pounds of lead 

 scrap into the shape of a disk, a hole 

 being made through the center for bolt- 

 ing the disk to the arm. The disk weight 

 must be fastened securely ; else the 

 movement will be jerky, and much 

 energy will be lost. In bending the iron, 

 it will be necessary to adjust it by 

 degrees until the board is found to bal- 

 ance freely on the pivot and come to rest 

 in a level position. 



The rocker leaves the operator free to 

 attend to other matters while develop- 

 ment is proceeding. If it is desired to 



open the darkroom door, a sheet of card- 

 board should be laid on the dish, and a 

 light-proof cover should be placed in posi- 

 tion. A cardboard box slightly smaller 

 than the board, makes a good cover, if 

 lined with two thicknesses of black twill, 

 with additional pieces at the corners. 

 This rocking arrangement is a time-saver 

 for any photographer. 



A Whole Tool-Box in One Tool 



THE day of the family tool-box may 

 soon be a matter of past history if 

 a device that is now on the market can 

 do all that its manufacturers claim for 

 it. The tool that threatens to do this 

 revolutionizing is 10 inches in length 

 and weighs 11 ounces. It can do every- 

 thing that a variety of household tools 

 can do and other things besides. Here 

 are a few of the tools whose work it 

 intends to accomplish: Hammer, lifter 

 for hot pans and dishes, tack-puller, 

 screwdriver, nut-cracker, box-opener, 

 wrench, pliers, rule, measure and ice- 

 chipper. It works automatically. 



This "Jack-of-all-tools" may be used to 



lift a hot plate off the stove or to hammer 



the tacks in the parlor carpet 



FULLY one-half of all the automo- 

 biles sold in the United States are 

 bought by farmers and others living in 

 rural communities. 



