194- Dr. Stenhouse on some of the 



If a solution of the powder which has been decolorized by 

 potash be cautiously neutralized by muriatic acid, the red co- 

 lour reappears, but is destroyed by the addition of more acid. 

 The iron is not precipitated by ammonia, even when added in 

 great excess, and the colour is only changed from a blood-red 

 to a deep reddish yellow. Hydrate of lime also destroys the 

 colour, precipitates the iron as peroxide and evolves ammo- 

 nia. If the red powder is dried at an ordinary temperature 

 it retains its bright colour, but if it is heated as high as 212° 

 F. it becomes reddish brown, losing its lustre. If first dried 

 at an ordinary temperature, it may be heated as high as 212° 

 F. without any reduction of its oxide. But if its solution is 

 kept for some time at 120° F., it is partially reduced; and if 

 boiled for an hour or so its red colour disappears, and the 

 peroxide of iron it contains is wholly reduced to the state of 

 protoxide. When dried at 212° F., and subjected to analysis, 

 the determinations of the iron double salt were as follows : — 

 I. 0-4-97 gave 0-1125 oxide=22-63 per cent. 



The last two determinations of the iron are omitted, as pro- 

 bably too high in calculating the mean quantity, —23-05 per 



G^tltt 



I. 0-3702 gave 0*4122 carbonic acid and 0-0705 water. 



II. 0-2390 ..* 0'27 .%v ... 0-051 



III. 0-4130 ... 0-468 0-0905 ... 



IV. 0-4983 ... 0-5665 0-113 



V. 0-3662 ... 0-4165 0-0760 ... 



I. 0-7052 grm. dissolved in alcohol acidulated with muriatic 

 acid gas and precipitated with an alcoholic solution of chloride 

 of platinum, gave 0-171 of platinum = 4-22 per cent, of am- 

 monia, or 3-49 of nitrogen. 



II. 0-4223 grm. of salt gave 0-1015 of platinum = 4-18 am- 

 monia, or 3-45 nitrogen. Mean 3-47 per cent, nitrogen. 



100-00 100-00 100-00 100-00 100-00 



