NOMENCLATURE Of CHEMISTRY. 19 



is left for a certain time in a fluid, and the mixture 

 is kept exposed to a slow degree of heat, the pro- 

 cess is called digestion. 



When one substance, which has an affinity to 

 another, is mixed with as much of that other 

 substance as its affinity will enable it to hold in 

 combination, then the former substance is said to 

 be saturated, or the mixture to have attained the 

 point of saturation,, If the mixture contain a 

 greater proportion of either substance, then that 

 mixture is said to contain an excess of it, or to be 

 surcharged. The same thing must be understood 

 of the compounds of more than two substances. 



The dry voay of performing chemical operations 

 is when strong degrees of heat are used, and the 

 humid way is when fluid solvents are used. 



Combustion is when a body is burned with the 

 assistance of respirable air. 



Deflagration is when the combustion is attended 

 with little explosions or cracklings. 



Detonation is a pretty loud report. 



OF THE NOMENCLATURE OF CHEMISTRY. 



One of the chief improvements which have been 

 made in modern chemistry has been the invention 

 of names for the compound substances, which ex- 

 press the elements which enter into their compo- 

 sition, as well as the proportions in which those 

 elements are combined. By this the memory is 

 much assisted, in recollecting the nature of the 

 great variety of substances, and to which the an- 

 cient chemists gave arbitrary and frequently unap- 

 propriate appellations. 



When the simple substances, oxygen, chlorine, 

 and iodine, which are supporters of combustion, 



