Popular Science Monthly 



435 



Spontaneous Combustion 



IT is not difficult to undcrsland iiow 

 combustion may take placi' without 

 any apparent cause. Consider some of 

 the everyday examples of combustion. 

 Coal requires a considerable amount of 

 coaxing before it will ignite, hence the 

 necessity to lay a fire with wood to start 

 the coal and paper to light the wood. A 

 poker at a bright red heat will ignite a 

 gas jet ; upon cooling to a dull red 

 heat it will set fire to paper; and after 

 still further cooling will explode gun- 

 powder. 



Phosphorus takes fire at a little above 

 ioo° F., by no means a high tempera- 

 ture. But the vapour of liquid phos- 

 phuretled hydrogen is even more easily 

 inflamed, requiring for its ignition a 

 temperature less than the ordinary 

 temperature of a room. Hence, when- 

 ever this substance comes into contact 

 with the air it takes fire at once. This 

 is an example of so-called spontaneous 

 combustion, and only differs from the 

 combustion of a candle in the circum- 

 stance that no outside source of heat is 

 required to start the reaction. 



Phosphuretted hydrogen can be made 

 by placing small fragments of yellow 

 phosphorus in a flask together with 

 some quicklime and covering with water. 

 Upon boiling the water phosphuretted 

 hydrogen is formed and escapes from a 

 bent glass tube passing through the 

 cork, the other end of the tube dipping 

 below the surface of warm water con- 

 tained in a dish. As each bubble of gas 

 comes into contact with the air it takes 

 fire and forms white powdery phos- 

 phorous pento.xide. — H. T. Gr.\v. 



This Loop Arrange- 

 ment Shifts theCon- 

 trol Back Into the 

 Hand 



The Phosphorus Powder Produces a Series 

 of Smoke Rings which Expand as They Rise 



Fitting Penholders to Crippled Hands 



AMOXC. the many appliances which 

 L have been devised to lessen the care 

 of soldiers injured in the war are various 

 kinds of penholders for those with 

 crippled hands. If the thumb and fore- 

 finger or the forefinger and middle finger 

 are stiff, or even if all three fingers are 

 not capable of bending, a holder in the 

 form of a loop may 

 be successfully 

 used. This 

 arrangement, in 

 which the control 

 is shifted back 

 into the hand, is 

 shown in Fig. i. 



If the thumb, 

 ring finger and 

 little finger have 

 been amputated, 

 a holder like the 

 one shown in Fig. 

 2 is of service. 

 The enlarged por- 

 tion enables the 

 index and middle 

 fingers to grip it 

 securely and also 

 keeps the holder 

 from turning. 



When the 

 thumb is good, 

 but all four fingers 

 injured so that 

 only their stubs 

 are left, a trian- 

 gular block is 

 made that fits the 

 palm of the hand 

 on one side, and 

 has a groove for 

 the thumb on the 

 other side. A 

 firm grasp can be 

 obtained by pres- 

 sure with the 

 thumb. This de- 

 vice is shown very clearly in Fig. 3. 



Casualties are so varied that no stand- 

 ard device can be established. Some are 

 injured in such a way that their hand 

 trembles when writing. A thick holder 

 of wood or cork, which only requires 

 holding but no bending with the fingers, 

 is very successful in this case. 



For Use Wheri 



Thumb and Two 



Last Fingers Have 



Been Amputated 



When the Hand of 

 the Injured Trem- 

 bles While Writing 



