292 
French Experimental Farm at Vavjuurs. 
It appears from analyses that a cubic metre of this Paris " soil" 
(about a ton) contains oi- kilogrammes of nitrogen, or about 
7;^ lbs. = i)^ lbs. of ammonia, the salts left after combustion 
amounting to nearly 19 lbs. On the other hand, an average ton 
oi London sewage (according to Professor Voelcker's analysis) 
contains only 3 J oz. of ammonia, and 2 lbs. of mineral matter, of 
■which ^oz. is phosphorus, and l^oz. potash. The vidavqc of 
Paris therefore contains forty times as much ammonia in a ton 
as the sewage of London. 
Means of Application. 
Next to the consideration of the fertilising powers of this niglit- 
soil comes the question of the most economical means of applying 
it, which M. Moll thus discusses. 
Tlie barrel mounted upon wheels, either with or without appli- 
ances for the even application of the fluid, has been in use I'rom 
time immemorial in Belgium, in the northern departments of 
France, and in Western Germany. It has the advantage of sim - 
plicity of construction, and consequently of small outlay in the 
first instance ; but in the end its employment is neither simple 
jior economical. 
It has been my fortune to employ under the same circum- 
stances the tubular system in its integrity ; that same system, both 
aided by gravitation and also in conjunction with the water-cart ; 
and lastly the cart filled by hand, and emptied either by direct 
action or the use of the " tub and scoop." The estimates I shall 
give are based on extensive trials, if not on continuous practice. 
A few preliminary remarks are desirable. When liquid 
manure is applied to growing crops the dressing must be much 
diluted : if it be urine {^jmrin '), with three or four times its bulk ; 
if night-soil, with five or six times as much water. Unless a 
favourable moment can be seized during or after rain, the dressing 
should be much more diluted than this. But at such times, from 
the wet state of the surface, the passage of the cart is often highly 
prejudicial to the land. The cart, then, cannot be well employed 
for growing crops in the season of their growth, neither is it 
suited to winter use. 
Any attempt to distinguish between the use of concentrated 
and diluted manures on the same farm, with a view to the em- 
ployment of the cart in the former case, must practically prove a 
failure : the mode of application will vary for different crops. 
The importance which some of the opponents of the tubular 
system attach to the employment of gravitation as a motive 
power, shows how little they are familiar with the subject. 
The great cost of this system consists not in the moving power 
or the apparatus required for laying on the liquid, but in the 
pipes. Even in our unfavourable position, where the boat to be 
