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 tlic 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, wliith 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 



