138 BEAT. 



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ignorance. The invention of this highly useful ad- 

 dition to the power of man, is owing entirely to the eluci- 

 dation of the laws and effects of this principle. 



Most men are familiar with some of the_most common 

 effects of heat, as they are exhibited in the course of every 

 day life; and yet there is but a small number who ex- 

 tend their inquiries beyond this and a still less number 

 who inquire into the why and wherefore, of these appa- 

 rently simple effects. Believing, therefore, that it is high- 

 ly useful to men to understand and comprehend what they 

 have learned by experience ; knowing that such knowledge 

 is highly pleasing, particularly to such as are conscious 

 of possessing the rich gift of an inquiring mind, we 

 propose to explain in a concise and elementary manner, 

 the effects and properties of heat, together with some of 

 its most important applications in the arts of life. 



EFFECTS OF HEAT. 



One of the first, and most common effects of heat upon 

 all bodies, whether solids, fluids or airs, is to expand 

 them, which may be shown by the following 



Experiment. Fit a rod of iron to a hole in some 

 metallic plate ; if it exactly fits when cold, when heated 

 it will be so enlarged as not to enter it. 



The same will be found to be the case with almost all 

 solid bodies. But all solids do not expand equally by the 

 same heat. Lead expands more than any other solid, 

 while glass expands the least. Numerous experiments 

 have been made by different philosophers, on the expan- 

 sion of solid bodies by heat, from which the following 

 conclusions are derived. 



A metal that has been condensed by hammering or 

 wire-drawing, expands more than when in a looser state ; 

 and those metals which melt the easiest, generally expand 

 the most. 



Advantage is taken of this property of solids, in many 

 of the arts and trades. Wheels are tired with iron which, 

 when cold, is a little smaller than the wheel ; and by being 

 heated it expands, and is thus placed upon the wheel, 

 after which it contracts by cooling, and thus binds all the 

 parts of the wheel firmly together. Large casks and 

 butts for brewers, &c., are rendered tight and secure by 

 placing hot iron or copper hoops upon them which, by 



