308 FLORIDA GEOLOGICAL SURVEY-THIRD ANNUAL REPORT.
wherever it is needed. The coke remaining in the retorts is an excellent fuel, too, said to be almost as good as anthracite coal.
A peat gas plant requires a larger investment than a peat briquetting mill, and in order to be profitable it must of course be located near a supply of peat large enough to last for many years. There are, however, quite a number of towns in Florida (Palatka and Lakeland, for example) Where conditions seem to be favorable for an enterprise of this kind.
Still another method of utilizing peat as a source of power is to convert its heat into electricity, through the medium of either steam or gas engines, right at the bog, and transmitting the electricity to neighboring cities or wherever it is wanted.
Peat is sometimes used as a fertilizer, by applying it directly to soils which are deficient in organic matter. For this purpose fresh peat should not be used, for it is too sour, not to mention other disadvantages. A better way is to let it lie exposed to the weather for a year or so before applying it to the soil, at the same time pulverizing it so that it will not be all hard lumps. This weathering process increases the availability of the nitrogen it contains, and makes it more and more like humus, as explained briefly in the introductory chapter of this report., The humification can be con siderably accelerated by mixing the peat throughly with barn-yard manure, for this contains bacteria which help to break up the peat, while the peat at the same time absorbs from the manure ammonia and other plant foods which might otherwise be lost.
In Florida there has been more capital invested in plants for the manufacture of fertilizer filler than in any other peat industry. Two of these have already been described on pages 287-289, and another briefly mentioned. All of these being situated on navigable waters, the first step in each case was to build a dredge and cut a canal from the water to the dry land where the buildings were erected.* The peat e,-cavated by the dredge from along the canal and its branches is carried on lighters to a dock, from which a belt conveys it to a "pug mill" similar to those used in mixing brick clay, which mixes and macerates it and lets some of the water escape. Then by an ingenious device of Mr. Ranson's, which need not be described in detail here, the peat is spread about eight inches deep over an area of several thousand square feet, to dry in the sun. No protection from rain is provided, but rain is infrequent in Florida in the winter and spring months, and in average
*For this description of the process of making fertilizer filler I am chiefly indebted to Mr. Robert Ranson, who designed all three of the plants under consideration.