82 CHARLES ANTHONY GOESSMANN 



sulphate of potash-magnesia on the quantity and qual- 

 ity of potatoes. Before the experiment had been in 

 progress long, a scabby condition of the crop resulted, 

 which led to a study of the cause of this trouble. Goess- 

 mann states that 'neither a liberal use of our own mix- 

 ture of commercial manurial substances rich in potash 

 compounds nor the selection of a fair quality of seed 

 potatoes from another locality had affected our results; 

 . . . for the entire crop with scarcely any exception was 

 badly disfigured by scab/ The conclusions were as 

 follows : 



(1) Medium-sized whole potatoes give better results 

 as far as a large-sized marketable crop is concerned 

 than half potatoes obtained from tubers of a corre- 

 sponding size. 



(2) The sulphate of potash produced better results 

 than muriate of potash. 



(3) Some peculiar condition of the soil is considered 

 the real cause of the scabby condition. (Photographs 

 of the scabby potatoes are given in the sixth report of 

 the Station, page 131.) 



It is evident that this scabby condition seriously 

 interfered with the experiment as originally planned. 

 It led to observations on the cause of the scab, and to 

 the conclusion that the seat of the trouble lay in the 

 soil. Later investigations by botanists showed it to be 

 a parasitic organism. 



X. Experiment with root crops (1887-1888). 

 A brief discussion is given of the general character of 

 roots and their place in the farm economy. Seed was 



