458
��ropitlur Science Monthly
���The Liquid is Thrown by the Pressure of Gas Generated in the Bottle
A Home-Made Fire Extinguisher
AN amateur mechanii- can casiK- L. make a fire extinguisher to work upon scientific principles the same as do the ones used in large buildings. As in the larger extinguishers, the liquid is thrown by the pressure of gas generated by mixing a solution of soda (sodium bicarbonate) and sulphuric acid. The materials necessary arc a bottle of about two Cjuarts capacity, a piece of glass tubing a little longer than the height of the bottle, a rubber stopper to fit the bottle, and a small straight medicinal vial.
By the use of an alcohol lamp, one end of the glass tube is heated and brought to a pcjint. The point is then broken of?, leaving a hole in the end about one-sixteenth of an in. in diameter, and the tube is bent.
If you cann(jt procure a stopper with a hole in it, one must be drilled to fit the glass tubing, whith should be about one- fourth in. in diameter. I'lie next step is to push the tube through the sto|)per so that the end of the tube almost touches the bottom of the bottle when the stopijer is in position. Tie a string around the small vial about one-half way between the middle ami the open end. (Seedrawing.) To charge ready for use, fill the bottle with .1 solution of i)aking soda so that there is barely room enough to hang the smaller vi.il inside
��the bottle clear of the solution. Next, fill the vial almost full of sulphuric acid and carefully lower it into the bottle, |)lacing the stopper in tightly so that the string suspending the small vial is held firmly between the stopper and the mouth of the bottle. In case of a blaze, grasp the bottle tightly in the hands, give it a few vigorous shakes to mix the two solutions and direct the stream of water (charged with carbon dioxide) on the blaze and it will be quickly extin- g u ished . — W'A I \ M a rti n .
A Towel Holder
A HANDY and practical towel holder can be made by the busy house- wifi". Remove the fasteners from worn- out and discarded garters and also the part that is attached to the stocking. Sew a small silver or brass ring to it. Fasten a towel to it as you would a stocking and hang it on a hook or a push-pin.
This holder can be used in places where a rack or rod might possibly be in the way. — Will Chapel.
The Strap as a Jar Opener
UNSCREWING the tops of jars is a simple operation with the aid of a shawl or belt strap. The strap can not slip because the harder it is pulled the harder it grips the jar. If the main part of the jar can be held to withstand the pull of the strap the most obstinate cover will have to capitulate. Where the ordinar\- types of jar openers do not fit the strap is an effecti\ e substitute.
���The Harder tht Strap Is Pulled the More Firmly If Grips the Jar. There Is No Possibility of Slipping or BrcakinR, Pro vidcd the Body of the Jar is Held Securely
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