836 



EXPEEIMENT STATION KECORD. 



sewage purification of cities and towns in Massachusetts. The results 

 of chemical and microscopical examinations of 212 different sources of 

 water supply in use in various cities and towns of the State are given 

 in this report. The experiments on the purification of sewage were 

 devoted mainly to tests of rapid methods, especially the method of 

 subjecting the sewage to decomposition and purification in a tank 

 .before appljang it to a filter. The usual tables of water supplv sta- 

 tistics are given, showing the number of towns supplied with water, 

 the quantity of water used, and a summary of the records of rainfall 

 and flow of streams. 



Nitrification and catch crops, P. Boxame {Rajy. An. Sta. A'jron. 

 {2f(iin'tth(H\., 1S9S~99, pjK S3-9If). — Experiments in continuation of 

 those of previous years (E. S. R., 9, p. 731) are reported. The follow- 

 ing table gives the principal results obtained in a study of the progress 

 of nitrification in a normal soil with or without the addition of nitro- 

 genous fertilizers and lime (calcareous sand): 



Amounts ofniiric nitrogen jxr 100 gm. of drij soil. 



Sulphate of ammonia (0.17 per cent nitrogen): 



Ordinary .soil 



Soil with 5 per cent of lime 



Dried blood (0.17 per cent nitrogen): 



Ordinary soil 



Soil with 5 per cent of lime 



Fertilizer (0.17 per cent nitrogen): 



Ordinary soil 



Soil with 5 per cent of lime 



Normal soil without addition of any kind (0.3 per 

 cent nitrogen ) ". 



Mc/. 



41 

 140 



91 

 140 



120 

 113 



Experiments with calcareous sand of 3 grades of fineness indicate 

 that up to 2 mm. in diameter the size of the grains is without effect 

 on the rate of nitrification. Lime applied at one-fifth the rate of the 

 sand was slightly more effective in promoting nitrification. Thomas 

 slag standing next to the sand in this respect, and sulphate of potash 

 third. Gypsum was practicall}' without effect. 



The rate of nitrification of some slowly nitrifying materials was 

 tested with the following results: 



Amounts of nitrogen per 100 gm. of (Jru soil. 



Pea leaves: 



Without lime 



With lime 



Compiist of cane leave; 



Without lime 



With lime 



Manure compost: 



W'ithout lime 



With lime 



Ordinary .soil: 



Without lime 



With lime , 



Mg. 



