6 EXPANSION OF LIQUIDS. 



very apt to split when they become hot, and much inconvenience 

 has often been experienced in manufactories from this cause. A 

 slight curvature in their form has been found to protect them 

 most effectually. 



Expansion of liquids. In liquids the expansive force of heat 

 is little resisted by cohesive attraction, and is much more consi- 

 derable than in solids. This ract is strikingly exhibited by filling 

 the bulb and part of the stem of a common thermometer tube 

 with a liquid, and applying heat to it. The liquid is seen im- 

 mediately to mount in the tube. 



The first law in the case of liquids is that some expand much 

 more considerably by heat than others. Thus, on being heated 

 to the same extent, namely, from the freezing to the boiling 

 point of water, 



Spirits of wine expand ^ that is, 9 measures become 10 

 Fixed oils T ' T 1.2 13 



Water ^.W 22.76 23.76 



Mercury -s4-5- 55.5 56.5 



Spirits of wine are, therefore, six times more expansible by 

 heat than mercury is. The difference in the heat of the seasons 

 affects sensibly the bulk of spirits. In the height of summer 

 spirits will measure 5 per cent more than in the depth of 

 winter. 



The new liquids produced by the condensation of gases appear 

 to be characterized by an extraordinary dilatability. M. Thilorier 

 has observed that fluid carbonic acid is more expansible by heat 

 than air itself; heated from 32 to 86, twenty volumes of this 

 liquid increase to twenty-nine, which is a dilatation four times 

 greater than is produced in air, by the same change of tempera- 

 ture.* Mr. Kemp has extended this observation to liquid sul- 

 phurous acid and cyanogen, which although not possessing the 

 excessive dilatability of liquid carbonic acid, are still greatly 

 more expansible than ordinary liquids. Sir D. Brewster had 

 several years before discovered certain fluids in the minute cavi- 

 ties of topaz and quartz, which seemed to bear no analogy to 

 any other known liquid in their extraordinary dilatability. They 

 do not appear to have been entirely liquefied gases, but probably 

 were so in part.f 



* Annales tie Chimie et dc Physique, t. 60, p. 427. 

 t Edinburgh Phil, Trans, rol. x. 1824. 



