50 
fixation of oxygene by the combustible body in a 
solid form, which takes place when most metals 
are burnt, or when phosphorus inflames ; or the 
production of a fluid from both bodies, as when 
hydrogene and oxygene unite to form water. 
When considerable quantities of oxygene or of 
chlorine unite to metals or inflammable bodies, 
they often produce acids ; thus sulphureous, phos- 
phoric, and boracic acids are formed by a union 
of considerable quantities of oxygene with sulphur, 
phosphorus, and boron : and muriatic acid gas is 
formed by the union of chlorine and hydrogene. 
When smaller quantities of oxygene or chlorine 
unite with inflammable bodies or metals, they form 
substances not acid, and more or less soluble in 
water ; and the metallic oxides, the fixed alkalies, 
and the earths, all bodies connected by analogies, 
are produced by the union of metals with oxygene. 
The composition of any compounds, the nature 
of which is well known, may be easily learnt from 
the numbers representing their elements ; all that 
is necessary, is to know how many proportions 
enter into union. Thus potassa, or the pure caus- 
tic vegetable alkali, consists of one proportion of 
potassium and one of oxygene, and its constitu- 
tion is consequently 75 potassium, 15 oxygene. 
Carbonic acid is composed of two proportions of 
oxygene 30, and one of carbon 11.4. 
Again, lime consists of one proportion of cal- 
cium and one of oxygene, and it is composed of 
40 of calcium and 15 of oxygene. And carbonate 
of lme y or pure chalk, consists of one proportion 
of carbonic acid 41.4, and one of lime 55. 
