Page:Popular Science Monthly Volume 91.djvu/123

 Popular Science Monthly

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��Flushing Streets with Water Pipes on Trolley Cars

IN Worcester and Springfield, Mass., the day of horse-and- wagon street flushing is past. Trolley cars carrying large water- tanks and electric pumps have been found much more effective and con- siderably more rapid. The pumps force the water out in such powerful streams that the trolley-car method has proved itself cleaner than the horse-drawn barrel-wagon from which the water flowed by gravity.

The pump supplies water to four pipes. Two of these lead to nozzles on the car itself and two lead to an arm which swings on the road-side of the car. This arm is swung back when automobiles or other obstructions are to be passed.

The flushing is done early in the morning after the cars have first gone the rounds in sprinkling the streets. The cars run at high speed so that an entire city can be cleaned by a very few of them in a very short time. With the old horse-and-wagon method speed was impossible. Sometimes the 'sprinkling had to be started during the night.

The added expense of the electric pump is balanced by the saving in the number of units and of men, so that the running ex- pense of the new method is not increased. On the other hand, only eighty-five per cent of the water formerly used is now required. The side streets which are not tracked are now flushed by connecting long hose to the street hydrants.

����Electric motors pump the water in four powerful streams that wash away every trace of refuse while the car runs at high speed

��Dr. L. L. Funk, using his mechanical broach wrapper and sterilizer. At no time during the process is the cotton touched by the hands

That Wad of Dental Cotton— Was It Sterilized?

IN cleaning the root-canals of affected teeth the dentist employs a wad of cotton wrapped on a steel needle. This wad is called a "broach," and is used in reaching the vital point where the nerve of the tooth passes out into the bony structure.

Usually the dentist twists the cotton around the needle with his fingers, which is neither sanitary nor safe in most cases. Dr. L. L. Funk of Chicago has invented the machine shown in the illustration. It does the wrapping mechanically, and sterilizes the cotton at the same time. Different meth- ods of sterilization are pro- vided for. The first is by means of dry heat of 275 degrees Fahrenheit, obtained from the electric heating unit; the second employs steam obtained by placing a four-candlepower electric lamp in a glass water-con- tainer and bringing the water to boiling point. This is used for moist sterilization and for melting inlay wax. A car- bolized sponge is used for sterilizing the needles.

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