460 MR. J. B. LAWES, DR. GILBERT, AND DR. PUGH ON 
From the result of the whole inquiry, the Commission announced the following con 
clusion :— 
That the experiment made at the Muséum d’ Histoire Naturelle by M. VILLE, 1s con- 
sistent with the conclusions which he has drawn from his previous labours. 
8. M. G. Vitir’s experiments in which the plants were exposed to free air, and Nitrates or 
Ammonia salts were employed as manure*. 
In 1855 and 1856, M. G. Vitis conducted a series of experiments with the double 
object, of investigating the action of nitrates upon vegetation, and of still further 
examining into the capability of plants to assimilate the free or uncombined Nitrogen 
of the atmosphere. The whole of the experiments now in question were made in free 
air, the plants being only shaded from rain; that is to say, without any enclosing appa- 
ratus, or artificial current of air and supply of carbonic acid. The soils consisted of 
calcined sand; ashes of plants such as those to be grown were added; and distilled 
water was used for watering. Colza and Wheat were the plants experimented upon. 
Lastly, the special conditions of the experiments were, that nitrate of potash in smaller 
or in larger quantity, or nitrate of potash and different ammonia salts, in equivalent 
quantities so far as their Nitrogen was concerned, were employed. 
To the prosecution of this series of experiments, an exact method of estimating minute 
quantities of nitric acid was essential. M. ViniE succeeded in devising such a method, 
which was very favourably reported upon by M. Pretovuzz, on behalf of a Commission 
composed of MM. Batarp, Penicgot, and PELovzE. 
In 1855, two pots, and in 1856 one pot, of Colzas were grown, to each of which 
0:5 gramme of nitrate of potash was supplied as manure. By examination of the soil, 
the point was ascertained when the whole of the nitrate had been drawn from it by the 
plants, The experiment was then stopped; and analysis showed that the total produce 
contained almost identically the amount of Nitrogen supplied in the seed and in the 
nitrate. The dry vegetable substance was, however, increased about 200-fold. 
Again in 1855, two pots of Colzas were sown, to each of which 1 gramme instead of 
0°5 gramme of nitrate was added; and in 1856 two more, with the same quantity. 
In each of these cases, the produce (which in dry matter was several hundred times that 
of the seed) contained considerably more nitrogen than had been supplied in the seed 
and in the nitrate. M.G. Vie’s conclusions were, that the plants had taken up the 
nitrate and assimilated its Nitrogen, and that when by the larger supply of nitrate the 
growth had been extended, the free Nitrogen of the atmosphere was also assimilated. 
In 1855 an experiment was made with Wheat manured with 1:72 gramme of nitrate 
of potash. The plants were allowed to mature, and they gave 84 grains. There was 
more Nitrogen in the vegetable produce alone, than in the seed and nitrate, and very 
much more in the total products, taking into account the residual Nitrogen in the soil. 
In 1856, two pots of Wheat were sown, to each of which 1:765 pramme of nitrate were 
added. The plants of one pot were taken up at the time of flowering, and they contained 
* Recherches Expérimentales sur la Végétation, 1857. 
