ON THE GASES EVOLVED FROM IRON FURNACES. 183 
so considerable as to fill in a very short time glass tubes of one-eighth of an 
inch in width, and we therefore endeavoured to obtain an approximative result 
as to the amount which thus passed over with the gases and escaped con- 
densation in the long tube. The opening of the iron tube was connected 
with an empty Wolf’s-bottle, to which another was attached containing water, 
in such a manner that the gas had to stream through a layer of four inches of 
the latter. The first of these bottles became quickly filled with a rich white 
sublimate of dry cyanide of potassium, while the water in the second became 
a tolerably concentrated solution of the same substance. It was now neces- 
sary to determine the quantity of gas which passed through the bottles, and 
this we ascertained by accurately noting the time employed in the experi- 
ment and the exact period necessary to fill a balloon of known capacity 
attached to the second bottle. 
1. Duration of the experiment, 24 minutes ; 
2. Mean time required to fill the balloon, 25 seconds ; 
3. Capacity of the balloon, 380°8 cubic inches. 
Hence it follows that 21933 cubic inches of gas passed through the bottle. 
The cyanide of potassium in the Wolf’s-bottles and their connecting tubes 
were made into one solution, which weighed 381-024 grms., and 129:211 grms. 
of" this solution yielded 0°62208 grm. cyanide of silver, which was easily de- 
composed by fuming sulphuric acid. Hence, in the 21933 cubic inches of 
gas which had passed through the flasks, there must have been 0°8944 grm. 
of cyanide of potassium held in mechanical suspension. We have already 
seen that the gas possessed the following composition :— 
Nitrogen . e « + « « « 58°05 
Carbonic oxide . * . « . 37°43 
ddydrogen 11/5) sie fe es BIB 
Cyanogen «6 «--, + + 6 1°34 
100°00 
The 21933 cubic inches of gas, admitting only its approximative estima- 
tion, its temperature being neglected, must contain 1192-97 grains of carbon, 
corresponding to 1774°79 grains of coal. Hence out of 100 parts of coal, at 
least 0°778 of cyanide of potassium are generated; and as 31200 pounds 
of coal are consumed every day in the furnace, it is obvious that at least 
2247 lbs. of cyanide of potassium are generated daily in the Alfreton fur- 
nace and hitherto have been altogether lost. 
When the iron tube used in the experiment was withdrawn from the fur- 
nace, it was found to be encrusted with melted cyanide of potassium, which 
speedily deliquesced in the air. On bringing it in contact with water, a con- 
siderable quantity of hydrogen gas was evolved, obviously due to the pre- 
sence of reduced potassium, or to its compound with carbonic oxide. In 
the tube itself at least three or four times the amount of cyanide of potassium 
was condensed, so that we may be quite certain that the amount formed is 
far more considerable than we have stated. With these unexpected results 
before us, it became of importance to determine the origin of the large quan- 
tity of potassium in the furnace. At first we conceived that it might be 
present in the limestone, which not unfrequently contains carbonate of potash, 
according to the researches of various chemists; but on examining as much 
as 30 grammes, we were unable to detect in it the smallest trace. However, 
we were informed by Mr. Charles Oakes that he had detected the presence 
of potash in the iron ore, and we are glad to be able to confirm the result of 
this talented young chemist. We have subjected an average sample of the 
