170 Dr, Thomas Thomson [Sept. 



racemate of soda, in powder, are introduced at the same 

 time, and then the phial must be well corked and agitated. 

 As the racemate of soda dissolves, the liquid becomes white 

 and opaque, and a soft white matter is gradually deposited, 

 which is racemate of iron. It may be collected on a filter, 

 and washed two or three times with cold water. But, as it 

 is not quite insoluble, we must not persist too long, other- 

 wise we would lose the whole salt. While drying, it assumes 

 a yellowish or buff colour, probably in consequence of ab- 

 sorbing a little oxygen. 



Racemate of iron obtained by this process is a soft powder 

 which adheres to every thing it touches. Its taste is sweetish 

 and astringent, like the other salts of protoxide of iron. 

 At 58° 100 parts of water dissolve 0-38 of this salt. The 

 solution has rather a deep yellow colour, and an inky taste. 

 100 parts of water, almost boiling hot, dissolve only 0*4 of 

 this salt, or very little more than water at 58° does. 



When the aqueous solution is evaporated to dryness, the 

 racemate is obtained in the state of a semi-transparent dark- 

 green crust, seemingly crystalline, though no distinct shape 

 could be made out. 



When the salt is raised to the temperature of 400° it takes 

 fire and burns like tinder, and the spontaneous combustion 

 continues though the vessel be removed from the sand-bath. 

 After the combustion is at an end, nothing remains but per- 

 oxide of iron. 



To determine the composition of this salt, 20 grs. of it, 

 previously dried in a gentle heat, were left for 24 hours in 

 the vacuum of an air pump, over sulphuric acid. The 

 weight was reduced to 12*95 grs. Being now heated to 

 400° it underwent spontaneous combustion, and left 4*7 grs. 

 of peroxide of iron, equivalent to 4*23 grs. of protoxide. 

 Now, 4*23 grs. of protoxide require for saturation 7*74 grs. 

 of racemic acid. Hence, the constituents of the salt are 

 Racemic acid . . . 7*74 or 8*25 

 Protoxide of iron . 4*23 ,, 4*5 



Water 0-98 „ 1-042 



This is very nearly 1 atom racemic acid . . 8*25 

 1 atom protoxide of iron . 4*5 

 1 atom water .... M25 



13-875 



