In this plant the aeration is conducted by blowing in air at the base of the condenser.
It should be observed that the free acid is gradually neutralized, partly by chemical action on certain constituents of the slime, partly by local action between different metals of the anode, both of which effect solution independently of the current, and partly by the peroxidation (or aeration) of ferrous sulphate formed from the iron in the anode.
But research showed that this process of nitrification is dependent on temperature, aeration and moisture, as is life, and that while nitre-beds can infect one another, the process is stopped by sterilization.
They serve probably for the aeration of the gonads by admitting to their vicinit y water with its dissolved oxygen; they never serve as genital ducts, since the generative products are always dehisced into the stomach and pass out by the mouth.
Again, the well-known action of earthworms may be said to be a biological work; but the resulting aeration of the soil causes edaphic differences; and earthworms are absent from certain soils, such as peat.
In the majority of cases the good results obtained are more particularly due to the setting free of " dormant " or " latent " food constituents and to the amelioration of the texture of the soil, so that its aeration, drainage, temperature and water-holding capacity are altered for the better.
Hydro-xerophytes (bog xerophytes) .Plants which live in ~t, peaty soils, and which possess aeration channels and xeroiilous leaves; e.g., Cladium Mariscus, Eriophorum angustifohium, if bus Chamaemorus, and Vaccinium Vitis-Idaea.
The stems are frequently characterized by aeration channels, which connect the aerial parts with the parts which are buried in practically airless mud or silt.
Related to the physiological drought, such plants possess some xerophytic characters; and, related to the physical wetness, the plants possess the aeration channels.
Even when all the conditions above mentioned in regard to texture, water-holding capacity, aeration and temperature are suitably fulfilled the soil may still be barren: plant foodmaterial is needed.
The efficiency of drainage, digging, hoeing and like operations is accounted for by the manner in which they promote aeration of the soil, raise its temperature and remove its stagnant water.