84 Dll. GOODMAN ON LIGH'J, MEAT, 



In another instance the thermometer indicated before com- 

 pression Q(3°, and after compression 67**, and no further in- 

 crease could afterwards be obtained in consequence of the 

 total destruction of the screw. 



Exp. 6. — On placing the thermometer upon and in con- 

 tact with the potassium itself, after the removal of the piston, 

 the heat indicated in a few moments was 72°. 



EXTEAOEDINARY ISSUE OP LIGHT AND HEAT FKOM 

 COMPRESSED POTASSIUM. 



Exp. 7, — The iron cylinder was again employed, six grains 

 of potassium were introduced, and the whole was placed in a 

 vice for compression. The thermometer indicated 70°. The 

 piston was depressed (after being firmly fixed upon the 

 potassium) -^ of an inch. To my astonishment, while 

 employed in turning the handle of the vice, three several 

 and successive explosions occurred, as loud as that from a 

 small pistol lightly charged, and were accompanied by 

 flame and smoke. 



It was discovered that the compressed metal had forced a 

 very minute slit or fissure between its own cell and that in 

 which the thermometer was inserted, and had thus ex- 

 ploded, leaving a stain upon the thermometer (which was 

 unbroken) resembling the marks of exploded gunpowder. 

 On removing the condensed potassium, it was discovered 

 to have the following qualities. It was apparently reduced 

 in bulk, which the depression of the piston indicated, was 

 harder and more friable, and consequently of greater 

 specific gravity, but that I was unable to ascertain. 



When placed in its own naphtha after compression, it 

 became somewhat heated ; for on placing the bulb of a 

 thermometer in contact with it, the instrument indicated a 

 rise of two degrees, but when removed into the open air in 

 contact with a thermometer, the increase of heat, indicated 



