1918.] PUBLIC DOCmiENT — No. 31. 43 a 



Time has been found for co-operative work with the Associa- 

 tion of Official Agricultural Chemists, Mr. Haskins serving as 

 referee on nitrogen for the year. 



(d) Vegetation Tests. 



In this division work has been continued, in co-operation with 

 the basic slag committee of the Association of Official Agri- 

 cultural Chemists, in the study of the availability of phosphoric 

 acid in basic slag phosphate. The work this season was for the 

 purpose of noting the residual effect of the different phosphates 

 used during the preceding year. 



One series of pot experiments with rape, comprising 18 pots, 

 has been completed to study the availability of phosphoric 

 acid in apatite and barium sulfide (Barium-Phosphate). 



Another series with millet, comprising 10 pots, has been 

 completed to study the crop-producing power of Nature's 

 Wonder Mineral Plant Food, a ground metamorphic rock which 

 has been advertised and sold under different names to a greater 

 or less extent in Massachusetts for several years. The results 

 have not been published, but fully substantiate previous ex- 

 periments with the material which show that it possesses but 

 little value as a source of plant food. 



3. Feed and Dairy Section. 

 A summary of the work of the feed and dairy section, in 

 charge of Mr. Smith, assisted by Messrs. Beals, Peables, J. B. 

 Smith and J. T. Howard, follows: — 



(a) The Feeding Stuffs Law (Acts and Resolves for 1912, 



Chapter 527). 

 During the past year 1,082 samples of feeding stuffs were 

 collected at 140 places of business. About 1,400 brands have 

 be^n registered and permits for sale issued. Four cases have 

 been prosecuted where goods ran substantially below guarantee, 

 and one case for failure to attach guarantee tags as required by 

 statute. In addition, a number of samples have been drawn for 

 the Federal government, and action is still pending. Although 



