74 HEAT OR CALORIC, 



3. METALS, &tc. Provide as many equal 

 cylinders of metals as may be desired ; fix 

 them vertically in a perforated copper or 

 iron plate, their lower ends resting on a 

 similar and parallel plate connected with the 

 upper one at a small distance by metallic posts. 

 Place upon each metallic cylinder a thin 

 slice of phosphorus, and set the apparatus 

 upon hot sand contained in an iron pan ; the 

 pieces of phosphorus will successively take 

 fire, in the order (caeteris paribus) correspon- 

 ding with the conducting power of the metals. 



I f * b * a 8 lass cy?d 76 *e others 

 the phosphorus upon that will not take fire.* 

 4. METALS AND WOOD. A solid piece of metal one and a half 

 inches in diameter, and eight inches long, closely wrapped in clean writ- 

 ing paper, will bear to be immersed in the flame of a spirit lamp, for 

 a considerable time, without scorching the paper ; but if the paper 

 be applied to a piece of wood, and heated in a similar manner, the 

 paper will immediately burn. L. u. K. 



5. Liquids almost destitute of conducting 



power. 



That liquids are almost devoid of power to 

 conduct heat is proved by the inflammation 

 of Ether, over the bulb of an air ther- 

 mometer, protected only by a thin stratum 

 of water. 



"The inflammation of ether, upon the 

 surface of water, as represented in this fig- 

 ure, does not cause any movement in the li- 

 quid included in the bore of the thermom- 

 eter at L, although the bulb is within a quar- 

 ter of an inch of the flame. Yet the ther- 

 mometer may be so sensitive, that touching 

 the bulb, while under water, with the fin- 

 gers, may cause a very perceptible indica- 

 tion of increased temperature." 



" By placing the sliding index I, directly 

 opposite the end of the liquid column in 

 the stem of the thermometer, before the 

 ether is inflamed, it may be accurately dis- 

 covered whether the heat of the flame cau- 

 ses any movement in the liquid." 



* Sometimes the phosphorus will melt in the air, without taking fire, but on 

 jarring the apparatus, it will blaze ; a thin film of oxidized phosphorus apparently 

 protects the phosphorus below from combustion. 



