PROPERTIES OF STEAM AND OTHER VAPORS. 



INTRODUCTION. 



FOR engineering purposes steam is generated in a boiler which is 

 partially filled with water, and arranged to receive heat from the fire in 



the furnace. 



The ebullition is usually energetic, and more or less water is mingled 

 with thr stcarn; hut if there is a fair allowance of steam space over the 

 r, and if proper arrangements are provided for withdrawing the 

 steam, it will he found when tested to contain a small amount of water, 

 usually between half a per cent and a per cent and a half. Steam which 

 contains a considerable percentage of water is passed through a sepa- 

 rator whirh rr moves almost all of it. Such steam is considered to be 

 approximately <: 



If the steam is quite free from water it is said to be dry and saturated; 

 '. from a boiler with a large steam space and which is making steam 

 -lowly is nearly if not quite dry. 



mi which is withdrawn from the boiler may be heated to a higher 

 tcm|KTature than that found in the boiler, and i* then said to be super- 

 Saturated Steam. Our knowledge of the properties of saturated 

 i and other vapors is due mainly to the experiments of Regnault,* 

 who determined the r of the temperature and pressure, the total 



heat of vaporization, and the heat of the liquid for many volatile liquids, 

 hN time, Rowland's determination of the mechanical equivalent 

 of heat has given a more exact determination of the specific heat of 



tcmjKTatures, and recently Dr. Barnes has given a 

 precise determination of that pro;>erty for water. Again, certain 



noblauch, Lindr and Klebe, has given us a good knowledge of the 



properties of im which can be extended to give the 



olumcs of saturated steam over a considerable range of tern- 



in the projHT place a comparison will be made with the usual 



theoretical computations for volumes. 



Mfmoirts d* r Imstitmt dt Fn**ct t etc., 



