Page:Popular Science Monthly Volume 90.djvu/777

 �FOR PRACTICAL WORKERS

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��A New Life-Preserver Made of Sheet Metal

METAL swimming plates have made their appearance in the field of life- preservers. These are called the safety-first buoyant swim- ming -plates and they con- sist of metal parts put to- gether just like two tin pie- plates soldered with their face? joining, allow- ing the space between them as a dead air chamber. The advantage of these plates lies in the fact that they will not rot or crumble like a cork life- preserver. A properly ap- plied paint prevents rust- ing, and they are always ready for use. They do not have to be inflated like the water wings which are used by some swimmers. There is no danger of leaks or punctures and the total weight of the appliance is about 3 lbs. The plates are not uncomfortable to wear and they allow a free arm movement to the swimmer. Three of the plates are joined together with a web band having a shoulder strap which buckles about the body under the arms, with two plates on the back and one on the chest. Small wire loops make the joinings.

����Adjusting the life-preserv- ers made of metal plates

��Using Straight Side Tires on Clincher Rims

CAREFUL application of tires is as necessary to good service as the selec- tion of correct si^e for the load, or rims of the

right design and regular meas- u r e m e n t. Straight side tires are some- times used on clincher rims, but in such in- stances filler beads should be fitted in the rim clinches to pre- vent the side walls of the tires from being chafed and gouged by them. To avoid, as much as pos- sible, the ten- dency of straight side tires to lift up from the rims at the inner edges of the cables and thus permit a rolling action sideways, it is considered advisable to have more spread between the cables than is necessary with the beads of the clincher type. The use of straight side cases on clincher rims is therefore discouraged. If best results are to be e.\- jjected from straight side tires they should be used only on straight side rims which are slightly wider at the base, and which permit of the necessary spread be- tween cables. Consider these cautions, and your tires will last longer.

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