EXPERIMENT STATION REPORTS. 



247 



placed in the pit, the solution obtained in this Avay to be compared bac- 

 teriologically and chemically with samples of the mixture itself. 



The water in the observation pit was pumped out and samples were 

 tested for soluble phosphates and for total nitrogen. In fact, the analy- 

 sis of this water was made from time to time to determine whether there 

 was any increase in these soluble salts. 



The analj^sis made on June IS, 1010 shows the amount of citrate sol- 

 uble phosphorus in the drainage water at the end of the first compost- 

 ing. This water was all pumped out before the second compost was 

 placed in the pit. The remaining analyses show that there was a con- 

 siderable increase of the citrate soluble phosi)horus in the drainage water 

 of the second mixture during the four montlis of comjiosting. If the 

 second compost had been left in the pit as long as the first, and the 

 same rate of solution had obtained throughout the period of compost- 

 ing as was noted during the first four months, approximately the same 

 amount of citrate soluble phosphorus would have been obtained in ten 

 months as for the first compost. 



The three analyses of total nitrogen on the water from the second 

 compost suggest that denitrification took place to some extent. All 

 chemical analyses with the exception of the pH values were made by 

 or under the direction of Mr. O. B. Winter of the P^xperiment Station 

 Chemical Laboratory. 



Bacteriological analyses were made from time to time of both the 

 second compost and the solution extracted from it, mainly for aerobic 

 and anaerobic cellulose decomposing organisms, for organisms causing 

 the solution of rock phosjdiate and for bacteria of the Azotohacter 

 species. The second compost was removed from the pit in October, 

 1919, and placed in four large bins from whit-li the first compost had 

 just been removed. After pumping out the water from underneath the 

 false bottom the pit was filled with leaves, mainly oak and maple, raked 

 from the campus (during the months of Xoveniber, 1010, and April, 

 1920) and were thoroughly tramped (\o\yy\ after each filling, the idea 

 being to imitate the formation of a natural i)eat from readily available 

 material. A pitcher pump reaching to the water underneath the false 

 bottom together with a distributing trough is being employed to keep 

 the entire mass in an active state of decomixtsition by i)umj)ing the 

 water from the bottom up over the top. A sample of this water ob- 

 tained early in June was found to be a very dark green, full of gas 

 bubbles and to have a bad odor. Analysis was made of this water for 



