180 On the Definite Propofrtions in which the [March, 



from 105*75 to 106*87 of oxide of leadj and mucate of lead is 

 composed o 



Acid ...48-33 100*00 



Oxide of lead 51*66 106*87 



99*9;) 



According to these experiments, mucous acid ought to saturate a 

 quantity of base containing from 7 '56 to 7'64 of oxygen. 



Mucate of lead treated by ammonia produces a submucate, but 

 of so glairy a consistence that it was impossible to separate it from 

 the liquid before part of it had absorbed carbonic acid ; so that I 

 was obliged to abandon the analysis of it. 



0*333 of mucous acid produced by combustion 0*149 of water 

 and 0393 of carbonic acid. This makes 5*26 per cent, of hydrogen, 

 31*9 carbon, and 62*84 oxygen. 



One part of mucate of lead, equivalent to 0*4833 acid, produced 

 0*21 water, 0*594 carbonic acid. This gives us per cent. 



Hydrogen 5*1 05 



Carbon 33*430 



Oxygen 61 -465 



100-000 



Now 7*66 X 8 = 61-28. Hence it follows that the acid ought 

 to contain eight volumes of oxygen. The other elements approach 

 six volumes of carbon and ten of hydrogen. This would make the 

 composition of the acid 



Hydrogen 5-018 



Carbon 34*164 



Oxygen 60*818 



100-000 



But there was some reason for suspecting that the hydrogen was 

 contained in it in nine volumes instead of ten ; so much the more 

 as I was not sure that either the mucate or the mucous acid itself 

 were quite dry. 1 thought it necessary to examine that point in the 

 following manner : — I heated mucate of lead till it lost its white 

 colour by dishy drogenization. The mucate analyzed gave 52-1 per 

 cent, of oxide of lead. Burnt in the apparatus so often mentioned 

 it gave 4"7 per cent, of the weight of the acid of hydrogen, and 35 

 of carbon. On the supposition that mucous acid is composed of 

 9H + 6C + 8 0, it ought to contain 4-54 per cent, of hydrogen 

 and 34-39 of carbon ; but 4-54 is less than 4*7, which the acid 

 (already a little burnt) produced ; therefore that acid must contain 

 more than nine volumes of hydrogen ; therefore the composition of 

 the acid must be 10 H + 6 C + 8 (J, and the excess of hydrogen 

 and oxygen found in the analysis must be owing to humidity. 



