Nitrification of the Soil. 
355 
offer a froo passa<^o to the air ; 3rd. The putrefaction of animal 
or vegetable substances ; 4th. Heat and humidity. 
In 1779 De la Kochefoucault and Dolomieu observed that 
chalk became nitrified when in contact with the air. " I believe," 
says Dolomieu, " that the discoveries relative to the generation 
of sahpetre may teach us also the principles of vegetation. In 
order to bring land to its highest state of perfection, does not the 
farmer, by repeated ploughing, expose the different parts of the 
soil successively to the action of the air ? Does he not mix with 
it animal and vegetable substances in a state of decomposition, 
and when the soil is too heavy and clayey, does he not apply 
calcareous marl to it ? All these operations are calculated to 
produce nitre with the greatest success ; and, in fact, there is no 
land in a high state of cultivation which does not yield nitre in 
a Hnely powdered state. From the above may it not be rationally 
supposed that one of the principles of vegetation — one of its 
primary causes of action — is this nitrous salt, the generation of 
which forms at present the object of scientific inquiry? The 
analogy between the means used for producing saltpetre and those 
used for bringing land to its highest state of fertility, might be 
continued still further ; but this simple sketch will suffice as a 
groundwork for further experiments with this double object." 
In 1778 Clouet and Lavoisier proved that the lime of Touraine 
and that of Saintonge nitrify very readily. 
In 1782 Thouvenel competed for and gained the prize at the 
meeting of the Academy of Science in Paris ; and he remarked 
that a basket of chalk, placed over blood in a state of putre- 
faction, produces a considerable quantity of saltpetre. 
In 1784 Cavendish demonstrated that nitrification requires the 
contact of an alkaline solution. 
In our own time Liebig, Boussingault, Barral, and Paul The- 
nard, have demonstrated that atmospheric air acting on a dunghill 
nitrifies it by degrees. 
M. Boussingault has recently proved in a memoir read before 
the Academy of Science in Paris, " that a part of the organic 
matter contained in manures generates nitrates in the same manner 
as they are produced artificially." 
The results which we here bring before the public are, there- 
fore, only the application of scientific facts demonstrated by 
chemists, who, following the example of Davy, have brought the 
light of chemistry to bear upon agriculture. 
This problem of artificial nitrification has been successfully 
solved by an experiment made at our farm — Britannia, near 
Ostend. The manure was placed on the top of the vault which, 
contains the urine, and covered with a light roof of asphalt felt, 
supported by uprights made of fir. The manure was divided 
2 A 2 
