72 Additional Notes. 



we may conclude that the latter consists of two ethers as well as the 

 former; and that they both, when separated by art or nature, com- 

 bine by chemical affinity when they approach, the one exploding, and 

 then consisting of a residuum after having emitted heat and light ; 

 and the other producing simply a neutralised fluid by their union. 



XI. Conclusion. 



1. When two fluids are diffused together without undergoing any 

 change of their chemical properties, they are said simply to be mixed, 

 and not combined ; as milk and water when poured together, or as 

 oxygen and azote in the common atmosphere. So when salt or sugar 

 is diffused in water, it is termed solution, and not combination; as 

 no change of their chemical properties succeeds. 



But when an acid is mixed with a pure alcali a combination is pro- 

 duced, and the mixture is said to become neutral, as it does not pos- 

 sess the chemical properties which either of the two ingredients 

 possessed in their separate state, and is therefore similar to neither of 

 them. But when a carbonated alcali, as mild salt of tartar, is mixed 

 with a mineral acid, they presently combine as above, but now the 

 carbonic acid flies forcibly away in the form of gas; this, therefore, 

 may be termed a kind of explosion, but cannot properly be so called, 

 as the ethereal fluids of heat and light are not principally emitted, 

 but an aerial one or gas; which may probably acquire a small quantity 

 of heat from the combining matters. 



But when strong acid of nitre is poured upon charcoal in fine 

 spowder, or upon ail of cloves, a violent explosion ensues, and the 

 ethereal matters of heat and light are emitted in great abundance, and 

 are dissipated; while in the former instance the oxygen of the nitrous 

 acid unites with the carbone forming carbonic acid gas, and the 

 azote escapes in its gasseous form; which may be termed a residuum 

 after the explosion, and may be confined in a proper apparatus, which 

 the heat and light cannot; for the former, if its production be great 

 and^&udden, bursts the vessels, or otherwise it passes slowly through 



