Chemical Changes in the Fermentation of Dung. 335 
With a knowledge of these facts I have no alternative but to 
differ from the high authorities I have named, and may venture 
to express a hope that chemists will investigate this subject in the 
field and not in the laboratory. 
It surely is a significant hint to farmers to accumulate as 
much of the green refuse of their farms as possible, and to fer- 
ment it with so much soil as to save the ammonia and other 
valuable compounds with which the decaying plants abound. 
It has been found that a ton of dry food and straw gives a 
quantity of farmyard dung whicli weighs — 
When recent 4G to 50 cwt. 
After six weeks 40 „ 44 „ 
After eight weeks 38 „ 40 „ 
AVhen half rotten 30 „ 35 „ 
When fully rotten 20 „ 25 „ 
The natural indolence of men who do not like to be troubled 
by innovation Avould explain these figures by the loss of water 
during fermentation, and so the. subject would be dismissed. 
But when so very much is at stake we earnestly beg men to lay 
aside the solicitations of indolence and to consider the matter 
fully. We ask no agreement in our conclusions but such as the 
truth of experience will warrant, ljut we do beg earnest atten- 
tion as a matter of national importance. Professor Johnston, 
from whom the extract is derived, says " A part of this loss may 
no doubt be ascribed to the evaporation of a portion of the water 
of the recent dung ; but the larger part is due to an actual escape 
of the substance of the manure itself^ The loss it will be observed 
is more than 50 per cent. Of this " the larger part" or more 
than 25 per cent. " is due to an actual escape of the substance of 
the manure itself," which signifies that a fourth part of every 
heap of "rotten muck" has been lost by the farmer who went to 
the expense of making it ! ! * 
formation of an unusual quantity of woody fibre, and thus diminished the propor- 
tion of sulphurised and nitrogenised matter, and retarded decomposition; never- 
theless when the mass (about three cartloads) was rotting the results were identical 
with those of last year. The man who removed the half-rotten mass said, " Eh yon 
things do stink; they fair took my breath when I flung 'em into the cart." If not 
polite this is certainly emphatic. Some radishes were dug into the land upon which 
they grew, and examined from time to time. When an individual radish was pulled 
out of the ground about half decayed, there was no difficulty in detecting free am- 
monia. By breaking through the envelope of woody fibre and shielding the root 
from the wind by the hand, the gas given off by the decaying interior would always 
affect turmeric paper. 
* Since the remarks in the text were written I have met with the following in 
an excellent little elementary work by Prof. Stiickhardt, p. 382 :— 
" The formation of Ammonia. — Put some gluten, some coarse flour or some peas 
into a flask, pour in some water and connect the flask by means of a glass tube 
with a second flask filled about an inch deep with water and let them remain in a 
moderately warm place. Insert also between the cork and the neck of the first 
z 2 
