The fixing the ammonia is the great difficulty the agriculturist experiences in all questions respecting those manures which naturally contain or produce it. Its volatility is so great that it not only readily escapes into the air, but carries along with it, especially from waters, bodies at the moment in a state of slow combustion; or, in other words, ferments, capable of exciting fermentation in other fermentable bodies.
It may even pass into the condition of caustic ammonia.[73]
[73] It is to be remarked that the specific gravity of ammoniacal gas is 53·619; can it be wondered at that this gas should carry bodies from waters which are in a state of slow combustion; during its transit through the air it may even become caustic ammonia?
In a well written pamphlet by Mr. Ward,[74] the unhappy and fatal mistake of mixing the surface drainage with the sewage of London is clearly pointed out for the hundredth time, but the parties who planned the scheme will no more take notice of such facts than they did fifteen or twenty years ago, when they commenced their work of polluting the Thames and other rivers.
[74] _Purification of the Thames_. A Letter by F. O. Ward, Esq., addressed to William Coningham, Esq., M.P. London: Renshaw, Strand.
To Mr. Ward’s proposal of purifying the river and fertilizing the land by tubular drainage, there are, however, many serious objections.
NOTE 2.--_Habits of the_ WILDE, _in desert or uninhabited countries._
It is known to sportsmen that in the neighbourhood of hills, partridges leave the low grounds at the approach of evening, and take themselves to the hilly or more elevated district. Nature has taught them a very curious fact in meteorology, namely, that on leaving the valley at night, and ascending the hill, the temperature of the air increases up to a certain elevation, and from that point upwards decreases. The game ascends to the point of highest temperature, and there remains for the evening. A friend informs me that whilst crossing the high range of mountains forming the watershed between the Grotevisch Rivière and the Zondag Rivière, in Southern Africa, he experienced as he ascended intense cold, with heavy dews in the valleys through which ran the sources of the Grotevisch Rivière, and these continued until he reached the base of the crowning heights. Here the party slept in a mud-hut belonging to a Dutch boer. During the ascent they saw no game; but on climbing about half way up the remaining steep before daybreak next morning, they reached a spot where all the large game had congregated. It was the point of greatest warmth, generally a few hundred feet above the plain, and below the summit of the mountain. From this point to the summit the cold was most intense, and snow lay on the high peaks of the mountains.