French Experimental Farm at Vaiijours. 
289 
Drainage. 
Diiiinage was on this farm a necessary preliminary to irri<:fa- 
tion ; but as it was estimated that lor the 217 acres this work 
would cost 1200/. (or nearly 5/. lO.s. per acre), a loan was re- 
Kpiired. When an application was made to the Company of the 
""Credit Foncier," the formal preliminaries required were found 
to be so tedious that the landlord, Mr. Smith, came forward and 
ofl'ered to make the required advance on the same terms as those 
prescribed by the company. 
M. Barbier, a well-known enoineer, was employed to plan 
and superintend the work, which was surveyed, certified, and 
paid for bv the Government Engineer of the district. As the 
work proceeded, the necessary advances were made, bearing an 
immediate interest of five per cent. The land of the left bank, 
42^ acres, has been already drained. 
Main drains, 2J inches in diameter, following the contour of 
the undulating surface, converge towards the old fen, in which 
basins have been formed to act as sinks (fosses a cuvette). 
I'ipes of 1"18 inch bore are laid from 13 to 16 yards apart, 
iit a mean depth of 51 inches, in a bed of clay mixed with sand 
and marl. To complete the circuit, air-drains are carried along- 
on a higher level, just as the head drains follow the depres- 
sions. The apex of the system is indicated by an air-chimney, 
in like manner as is the lowest point of outfall by the well which 
acts as a cesspool. " Tliere is thus a double circulation ; whilst 
the water flows downwards the air is constantly mounting up- 
wards, penetrating the soil and conveying oxygen to the manure 
which is being consumed and transformed by the process of slow 
combustion." 
Lastly, from the lowest point in the fen a 12 -inch tunnel is 
run to the Bridge of Villepinte at a depth of 13 feet, where it 
empties in a cascade into the canal the drainage water from 
the left bank. 
At the date of the publications referred to the work on the 
right bank was still incomplete, there being here greater diffi- 
>culties to contend against, arising from want of fall and difficulty 
of securing an outlet, which made it necessary to deepen the 
tunnel and to construct main drains in boiling sand. As far as 
it has gone, the work has cost 6/. per acre, but the outlay cannot 
be fairly stated till the work is finished. 
Pipiiif/. 
Next in importance to the work of drainage, if not in this 
case of more special interest, was the organisation of the appa- 
ratus for irrigation, which was a work of time. 
VOL. XXIII. U 
