Ixiv. =—s- Historical Sketch of the Physical Sciences, 1818. 
Thus common salt, by this treatment, becomes chloride of so- 
dium. Davy, accordingly, states that these chlorides are mca~ 
pable of being decomposed by vitreous phosphoric, or boracic 
acid ; but that they are readily decomposed by these bodies, 
and muriatic acid gas disengaged, when their action is assisted 
by the presence of water. This assertion has been lately put 
to the test of experiment by M. Vogel, of Munich. He ex- 
posed muriate of barytes and pure phosphoric acid to a strong 
heat in two separate platinum crucibles, then mixed them to- 
gether, and exposed the mixture to ared heat in a platinum tube; 
abundance of muriatic acid gas was disengaged. When mu- 
riate of tin and muriate of manganese were substituted for mu- 
riate of barytes, the result was the same. Hornsilver likewise 
yielded muriatic acid gas, but in smaller quantity than the other 
salts. Superphosphate of lime may be substituted for phosphoric 
acid with the same result. When boraciec acid is heated in the 
same way in contact with the alkaline muriates, muriatic acid 
gas is hkewise disengaged.—(Jour. de Pharmacie, 1819, p. 61.) 
These experiments are directly contrary not only to the expe- 
nments of Davy, but likewise of Gay-Lussac and Thenard, 
the chemists, who first drew the attention of chemists to the 
true nature of chlorime——(See Recherches Physico-chemiques, 
ii. 103.) Hence, before they can be admitted as accurate, 
they will be required to be verified by other experimenters. I 
think it most likely that the acids used by Vogel had not been 
quite freed from water. Whether it be possible to drive off all 
the water from them by heat is a question of rather difficult 
determination. As far as phosphoric acid is concerned, I should 
be disposed to answer in the negative. 
To Vogel we are indebted likewise for a set of experiments 
to. determine the action of sulphur on the muriates. The result 
was, that the following metalline muriates were decomposed 
when heated with sulphur: 
Protomuriate of tin, 
Muriate of copper, 
Muriate of manganese, 
Muriate of lead, 
Muriate of antimony, 
Protomuriate of mercury, 
Permuriate of mercury. 
Sulphurous acid gas, and in some cases sulphuretted hydrogen 
gas, were exhaled, and a metallic sulphuret formed. Hence it 
appears that the sulphur deprives the metal of its oxygen. It 
appears also in some cases to decompose the muriatic acid. The 
muriates of potash, soda, and barytes, are but very tee acted 
on when treated in this manner.—(See Annals of Philosophy, 
xii. 393.) - 
