334 Chemical Changes in the Fermentation of Dung. 
One expeiiinent upon a larger scale was most notable. Three 
or four cartloads of waste radishes were placed to ferment and 
allowed to remain for three weeks, and when they were removed 
(June 25, 1853) nearly the whole mass was rotten. Upon coming 
up to the labourer who was set to remove them I was surprised 
to find him standing back from the heap with his eyes watering 
and apparently just recovering his breath. My own nose how- 
ever soon told me the reason, for the quantity of ammonia given 
off was such that it was impossible to breathe with the head 
held closely over the heap. One or two other men who smelt 
the gas believed I had mixed ' hartshorn ' with the heap. From 
no equal quantity of either animal or vegetable matter did I ever 
observe an ec^ual escape of ammonia. 
Unfortunately I am not able to state what other gases were 
given off. I left the spot to procure the means of testing it, 
and upon my return had the mortification of finding that the man 
had made an end of his ' nasty job ' and had removed the mass 
to an adjacent dunghill, I had omitted to tell him to leave it 
till I came back.f 
growth, but none had flowered or seeded. They were wheeled upon a heap which 
slightly consolidated it. This heap was not touched till fluid had run from the 
bottom three or four days, when a hole a foot square was cut in its centre by a spade 
nearhj but not quite to the bottom. Next day this hole contained some fluid, and 
in two or three days almost a gallon at a time could be collected. The smell to 
leeward now became insufferable even at nine or ten yards' distance. Several 
labouring men, who had been brought up gardeners and farmers, described it as 
smelling stronger than any 'ashplace' they ever emptied." A friend (an intelli- 
gent amateur farmer) to whom I showed part of a bottle of the liquid could hardly 
believe it other than an artificial preparation of " stinking fish in stale urine." 
One still afternoon I placed some hydrochloric acid in a soup-plate upon the heap, 
when a wreath of white fume arose, which was easily visible at 200 yards' distance. 
Two men at work in the next field were attracted by the ' smoke,' and " cou'du't 
think how the green lump of muck could catch fire," and they actually laid down 
their tools to come and see. I subsequently asked them how far off the ' smoke ' 
could be seen ? One said half a mile, the other a quarter ; and to the latter state- 
ment both adhered firmly as being quite within the truth. 
This popular mode of exhibiting the subject will probably weigh more with 
practical men than the most elaborate analysis. 
I am not at liberty here to say anything relative to the incalculable damage done 
by weeds ; but it is to be hoped that farmers will draw the inference which it does 
not seem easy to miss. 
I may perhaps be excused for adding a caution to those who feel disposed to 
investigate this subject for themselves. They should keep as much as possible on 
the windward side of the heap, and in manipulating with the fluid should choose a 
place where a draught will carry from them the evolved gases. Notwithstanding every 
precaution against inhaling the gases given off, I was made ill by them for more 
than a week, and my eldest child, a boy of seven years of age, was seized with all 
the symptoms of typhus after smelling (in the open air) the contents of a bottle to 
which a strong acid had just been added. 
t Uailislies. — An experiment was made this year (18.'55) to confim the one above 
given. The very dry spring was unfavourable for this purpose, as it caused the 
' Nightsoil and ashes form one of the principal manures in this neighbour- 
hood. 
