EXPERIMENTAL WORK WITH CRANBERRIES. 63 



removable roof of boards which is further covered by cornstalks and hay 

 to a depth sufficient to completely protect the interior from external 

 temperature. As soon as freezing weather is over in the spring the cover- 

 ing of litter is removed, and later, at the proper season for draining the 

 bogs, the roof is taken awa}\ 



The drainage from a cranberry bog consists of two quite distinct por- 

 tions, namely, the run-off from the surface and the seepage from the soil, 

 while there is the ditch water at the beginning of drainage, which is a 

 mixture of both kinds. On a properly graded bog nearly all the surface 

 flowage should run directly into the ditches without seeping through the 

 soil. On the other hand, water retained by the vines and in depressions 

 in the surface of the bog, together with the water held in the pore-space 

 of the sand and peat above the level of the sluice gates, must either evap- 

 orate or sink lower into the bog, and as it settles it displaces the saturated 

 bog water, which seeps into the ditches. 



The composition of the three types of drainage water has been carefully 

 followed season by season, and it is believed that some light has been 

 obtained on the probable losses of fertilit}^ 



The surface water is removed from the experimental bogs bj'' means of 

 a dipper, because their construction does not permit it to be drawn off 

 otherwise without losing its identity. Its composition has been found 

 to be essentially like any surface water from ponds and streams. The 

 surface waters from four bogs that had been top-dressed with a complete 

 fertilizer in 1911 were examined in the spring of 1912, in comparison with 

 the surface water from four bogs which had received no fertilizer. Total 

 solids and organic solids were first determined with the following results: 

 surface water contained in 100,000 parts, 16.0 parts total residue and 4.8 

 parts organic matter from the fertiUzed bogs while the surface water from 

 the unfertiUzed bogs contained 19.2 parts total residue and 6.4 parts 

 organic matter. No nitrates were found, and as the fertiUzed bogs had 

 not imparted any increase of soluble matter to their flood waters it was 

 not deemed worth while to carry the analysis further. The run-off cannot 

 be considered as removing from the bogs any serious amount of fertilit}'', 

 since its composition cannot vary widely from the water when applied, 

 except for the soluble matter that is extracted from the vines. 



The water standing in the small cylinders at the time the surface water 

 was dipped from the bogs is nearly the counterpart of the ditch water after 

 the run-off has past and seepage begins. That is, it is a mixture of surface 

 water and seepage water. A number of analyses have been made of the 

 water at this stage, because there are possibihties for considerable varia- 

 tion, and it will be noted in the table that there is a ^vide range between 

 the two seasons. 



