Popular Science Monthly 



m\ 



half lime cask and place it over the center of 

 the bottom of the larger one. Mark 

 around it with a pencil and saw out the 

 resulting disk with a keyhole saw. Fit the 

 lime cask in this opening and nail it 

 securely in place. Arch over the bottom of 

 the large cask and build up around the 

 smaller one with a somewhat richer mixture 

 of cement, about I part cement to 2 parts 

 sand and 2 parts stone. In rounding over 

 the edge of the large cask do not spread the 

 cement less than 2 in. thick at any point. 



For a cover, make a mold by nailing a 

 barrel hoop around the edge of a barrel- 

 head; lay in a few pieces of scrap wire, etc., 

 to act as binders and pour in a 2 to 1 mix- 

 ture of cement and sand. Insert an iron 

 ring in the center for a handle. Allow this 

 to set a week before removing the mold. 

 After all has hardened at least two weeks 

 fill in and cover with earth. Such a cess- 

 pool has given good service for nearly six 

 years. — L. B. Robbins. 



Pedal-Operated Brake for a Belt- 

 Driven Motorcycle 



THE only brake that can be used on a 

 belt-drive motorcycle is the friction 

 clutch in the rear hub controlled by the 

 starting ped- 

 als. Just to 

 be more up- 

 to-date I ap- / ,^S=====^ 

 plied the at- / /x^\io7 

 tachment / //^ nd stop ^ 

 shown in the 



A sliding dog on a motor- 

 cycle frame for a pedal brake 



accompanying 

 illustration to 

 operate this 

 brake with a 

 foot-pedal. 

 The main 

 support of the 

 brake is 

 mounted on the frame-brace so that it 

 will move freely. The wire to the foot- 

 lever is attached to the extension on the 

 dog, so that when pressure is applied to the 

 foot-lever the lower part of the dog catches 

 in the chain. The roller prevents the 

 chain from pushing away from the dog. 

 After the dog slips over a link-pin it cannot 

 go farther. As the foot-pedal is pressed 

 down the whole attachment moves forward 

 on the frame-brace, pulling the chain back- 

 ward and setting the clutch-brake. When 

 the foot releases the pedal-lever the spring 

 pushes the dog and support back. 



Making a Soldering Iron Heater 

 of Pipe and Fittings 



THE main body of the heater A is a 

 piece of J^-in. iron pipe 12 in. long, 

 threaded on both ends to receive a cap B. 



Pipe and fittings as they are used to make a 

 gas burner for heating a soldering iron 



A portion of one end equal to the length of 

 the soldering copper is perforated or drilled 

 to produce two rows of 1/16-in. holes at C. 

 Located in the center are two feet or sup- 

 ports to raise the heater from the bench 

 surface. These supports have the form 

 shown at E. These are made of sheet 

 metal about 1/16 in. thick and % in. wide. 

 Holes are drilled near the top of these 

 pieces and nails F inserted to form a rest 

 for the iron. The supports are secured to 

 the pipe with machine screws as at G. At 

 the opposite end of the pipe a small piece is 

 cut out as at H to supply the necessary air 

 to the gas. 



The nozzle for the gas jet is made of a 

 piece of ^8-in. brass pipe about 3 in. long, 

 flattened at one end as shown. A hole is 

 drilled in the cap for this end of the main 

 pipe and the piece of brass inserted with 

 nozzle end in and near the air inlet notch. 

 A rubber tube is used to connect the heater 

 with a gas supply pipe. If the heater gives a 

 large white flame the end of the brass 

 tubing / should be flattened more. The 

 right flame can be determined by trial in 

 changing the size of the opening. 



A Durable Paint for Surfaces Exposed 

 to the Weather 



SEVERAL tests made with paint on boards 

 showed that a mixture of one-third 

 zinc white and two-thirds barites was the 

 most durable. The large amount of oil 

 required prevented the reaction of the 

 zinc, but the paint was deficient in body, 

 hence in covering quality. 



