520 EXPERIMENT STATION RECORD. 



[V 



reasons for the need of lime in soils; to point out the indications of that lic.il 

 and its distribution over the State; to explain the different fornrs of lime that 

 may be used, and to point out their limitations and advantages; to give some 

 directions for the use of lime; and finally to pi-esent briefly data showing the 

 value of lime as a means of soil Improvement as revealed in experiment station 

 tests and in farm demonstrations." 



Ijimestone resources of Pennsylvania, F. J. Holkkn and W. Fkkar ( Penn- 

 sylvania Sto. h'pt. 1916, pp. .'i23-.'i.'i.'t). — This is a supplementary report (10. S. R., 

 38, p. 22) containing desci'iptions by counties and analyses of ir)2 samples of 

 limestones occurring on Pennsylvania lands and received front landownei-s 

 who desired information as to their agricultural value. 



Analyses of 23 samples of commercial ground limestone, burnt and hydratcd 

 lime, and limestone by-products are also included. 



Lime report 1019, J. W. Kellogg {Penn. Dcpt. Ayr. Bui. 336 {1020}, pp. 

 37). — This bulletin reports the results of actual and guarantied analyses. of 

 187 samples of lime products for agricultural uses, representing 60 brands 

 registered for sale in Pennsylvania during 1919. In addition, the text of the 

 State lime-inspection law is given, together with discussions of important 

 features. 



By-products from sewage sludge, II. S. Weston {Anier. Jour. Pub. Health, 

 10 (1920), No. 5, pp. 405-409). — lu a review of data on the subject it is pointed 

 out that the most promising of the sludges from the standpoint of the recovery 

 of by-products are those of the activated sludge and the Miles acid proces.ses. 



" The cost of aeration and acid treatment are not far apart, and the more 

 valuable IMiles process shidge contains less water and is much more stable 

 than the bulkier and partially defatted activated sludge. Repeated experi- 

 ments have shown that many American sewages contain enough fats and 

 fertilizer constituents to make the problem of their recovery worth considera- 

 tion. This is as far as the art has progressed in this country, but in England 

 . . . certain cities using the Miles process recovered grease and fertilizer 

 at a profit. Furthermore, a drier has been brought out which promises suc- 

 cess with American sewages, and Dorr has suggested a method for avoiding the 

 process of dewatering sludge to a point where it can be handled in a healed 

 drier. This brings the process to a point where a large scale experiment is 

 necessary. In this experiment various proces.ses for making sludge and for 

 handling the same should be tried side by side, and devices like the Dorr 

 thickener and the B. T. W. drier should be valued." 



Can the farmer mix his own fertilizers? F. W. Taylor (New HanipsJiire 

 Sta. Circ. 21 {1920), pp. 3-8). — Analyses of 21 samples of home-mixed fertiliz- 

 ers obtained from farmers in New Hampshire are reported and discussed. 



It was found that the average of the nitrogen determinations of the 21 

 samples was within 0.06 per cent of the amount calculated. The average 

 percentage of phosphoric acid was 2.34, and of potash 0.97 per cent higher 

 than that calculated. 



It is stated that variations almost as wide as these were found in 34 samples 

 of complete factory-mixed fertilizers. The rather wide discrepancies in the 

 phosphoric acid figures are attributed to the assumption that there was a , 

 smaller content of available phosphoric acid in the mixing ingredients than 

 actually existed. It is considered true that the farmer can mix his own 

 fertilizers fairly well. 



Report of analyses of sami)les of commercial fertilizers collected by the 

 Commissioner of Agriculture during 1919 (New York State Sta. Bui. 467 

 (1919), pp. 61-112). — This bulletin presents the results of actual and guarantied 



