SOME FLORIDA LAKES AND LAKE BASINS.

day. The well continued spouting without interruption for a little more than a week and until shut off by the owner.
Various fanciful theories have been advanced to account for the spouting, including supposed occurrence of gas and oil, and the supposed influence of recently formed sinks in the interior of the State. The true explanation is evidently much more simple. At the present stage of the lake the well is receiving water at less than its full carrying capacity and as the water enters the vertical pipe it forms a suction carrying a large amount of air into the well, which doubtless collects in a chamber or cavity along the side or at the bottom, of the well. As the well continues receiving water the air accumulates under pressure in this chamber until ultimately the pressure under which the air is confined is sufficient to overcome the weight of the overlying water and hence rushes out with considerable force carrying the column of water with it.
The fact that the well when first drilled did not spout and afterwards began spouting doubtless indicates that the essential conditions were subsequently developed either by caving or by other changes in the underground conditions.
The spouting of the well is therefore on the principle of the nirlift pump in which air under pressure is conveyed into the well through a special tube for that purpose and being liberated in the well lifts a column of water to the surface. In this spouting well, however, the air pressure is developed within the well. This well may, therefore, be classed as a self pumping well.
When partly shut off so that only a limited amount of water enters, the air taken into the well is able to return to the surface freely. Under these conditions spouting ceases. It is probable that if an elbow is placed on the well, allowing the water to enter laterally instead of vertically, the amount of air taken into the well will be so far reduced that the spouting will cease. Likewise when the lake rises so that the water stands several feet above the top of the pipe entering the well it is to be expected that the spouting will cease, since the pipe will then be carrying water at its full capacity, and little or no air under these conditions entering the well.*
The drainage wells are themselves remarkable and found in such perfection only under geological conditions similar to those existing in Florida. Of the many peculiarities of these wells,
*Since the above was written very heavy rains attending the storm of October 17, 19I0, caused the lake to rise 18 or 20 inches, and Mr. Unis writes that when the water rose in the lake the well ceased spotiting. A similar well at Albany, Georgia, is reported by McCallie. Science, XXIV, p. 694, 1906.

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