Page:Popular Science Monthly Volume 89.djvu/192

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��Pofular Science Mhnthly

��Extinguishing an Oil Fire with Carbon-Dioxide Foam

FIFTEEN thousand gallons of gas- oline were set on fire recently at the Greenpoint plant of the Standard Oil Company to test carbon-dioxide foam as an extinguishing compound. The oil was allowed to burn for about a minute during which time the flames and smoke gained such headway that a column of it mounted three hundred feet in the air. At this point the carbon-di- oxide foam was turned on, and it was so effec- tive that the fire was within control in a very few sec- onds and en- tirely out with- in forty-four seconds.

Most of the big oil tanks of the country are now protected by an auto- matic device which releases carbon -dioxide foam in quanti- ties sufficient to put out the biggest fire. Where a tank explodes, how- ever, other measures have to be taken.

���Thi oil was allowed to bum for a minute when the carbon -dioxide foam was forced into the blaze from the pipe which is shown at the left of the picture

��Sand is most frequently used in these emergencies, and water, used in the early days of oil fire-fighting, is now never used, since it is heavier than oil and causes the gasoline to overfiow and thus spread the fire insteail of confining it.

Where vats of highly inllamniable liquids such as benzine, naphtha and kerosene are stored, they are e(|uipped with pipes so that they can be drained.

��Locating Guns by Delicate Earthquake-Detectors

SCIENCE has discovered that gun- fire affects the earth's surface much like an earthquake, so it is not surprising to learn that guns are being located by the seismograph — the delicate little in- strument which records terrestrial trem- ors. An Aus- trian authority on the subject of earthquake disturbances announces that the seismo- graph can record the po- sition of hostile artillery as well as the caliber of the guns.

In the fairly recent engage- ment between Italian and Austrian troops at Ison- zo, the tremors induced by the heax'y cannon- ade were duly registered by the apparatus, and the opera- tor was able to detect, by means of dia- grams of arti- ficial m o V e - ments of the ground, the difference between the shocks pro- duced by the fall (if projec- tiles anil those caused by the recoil of the guns. More- over, the form of tlic tracings revealed to the practiced eye the number as well as the caliber of the latter. From these results came the suggestion that movable seisniograpliir stations ten to twelve miles in the rear of the trenches and con- nected with them by telei>hone would enable trained observers to transmit infcirniatiiin to the commanding othccr.

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