Intelligence and Miscellaneous Articles, 395 



oxygen was received over water, and the metal weighed after calci- 

 nation. 



Four analyses of the protoxide of gold dried in vacuo, and obtained 

 by different processes, were performed ; in the first two experi- 

 ments the protoxide was obtained with nitrate of mercury ; the third 

 from protoxide obtained by potash from the chloride ; the fourth 

 from tritoxide and potash. In the last two cases the gold was treated 

 before weighing with hydrochloric acid ; for the oxide thus obtained 

 always retains a little alkaline sesquicarbonate, which is not removed 

 by washing. 



The volume of oxygen obtained, reduced to weight, gave the fol- 

 lowing results as the composition of the protoxide of gold in 100 

 parts : — 



Oxygen.. 395 3-85 3-52 3-78 



Gold 96-05 96-15 96-48 96-22 



100- 



100- 

 M. Figuier considers the protoxide of gold as composed of 

 One equivalent of oxygen . . 100 

 One equivalent of gold .... 2486 



2586 



PROPERTIES OF OPIANIC ACID. 



M. Wohler states that opianic acid crystallizes in small slender 

 prisms, often as arborizations and usually reticulated. It is colour- 

 less, though it is not always obtainable without a slight yellow tint ; 

 it is but slightly soluble in cold water, but very readily in hot, so that 

 a saturated boiling solution becomes almost one mass by cooling ; it 

 is also soluble in alcohol and in aether ; it fuses at 284° without 

 losing water ; it rises up the sides of the retort when heated in one, 

 and distils without being properly volatilized ; when heated in the 

 open air it smokes, and volatilizes with an aromatic odour, somewhat 

 resembling vanilla, and is very much like that which narcotina gives 

 out when decomposed. The vapour is inflammable and burns with 

 a sooty flame. 



Opianic acid which has been melted by heat remains soft and trans- 

 parent several hours after it has become cold, and may be drawn out 

 into threads like turpentine. It afterwards begins to become opake 

 and hardens at the surface, so slowly, however, that in pieces of con- 

 siderable size a vitrified portion remains, as happens with arsenious 

 acid. "When examined in this state by the microscope, no well-cha- 

 racterized crystallization is perceptible in the opake hard portion ; 

 and it is very remarkable that the acid has become insoluble in 

 water, alcohol or dilute alkaline solutions. If it be put into water 

 while it is transparent and be then heated, it becomes milk-white 

 in an instant ; on boiling it is converted into an earthy-white mass, 

 a very small portion of which is dissolved and deposits on cooling in 



