536 Circular No. 6. 



(/) A substance which may be conveniently used, 



(2) A substance which will neither retard nor prevent germina- 

 tion. 



(j) A substance which will effectively deter crows, and possibly, also, 

 rodents. 



(4) A substance which will not interfere materially with the operation 

 of seed planting. 



EXPERIMENTAL TESTS 



Considering the practices now more or less commonly employed it 

 seemed desirable to give the coal tar a careful experimental trial, and, 

 at the same time, to employ other substances with objectionable odors 

 or tastes. Accordingly, experiments were arranged for the treatment of 

 seed with the following substances, namely, coal tar, pine tar, oil of 

 turpentine, anilin oil and pyridine. The results may be discussed in the 

 order of the requirements above given. 



(/) Some difficulty was anticipated in securing a more or less equal 

 distribution of the small amount of tar upon so large a volume of seed, 

 but it was found that this could be accomplished by repeated stirring, 

 or shovelling of the seed. Tar at the rate of one or two tablespoon- 

 fuls per ten quarts of seed was sufficient effectively to coat almost every 

 seed in the mass. This was true in the case of both the coal and the 

 pine tars. It was therefore evident that any of the materials mentioned 

 could be employed so far as convenience is concerned. In employing 

 pyridine and anilin oil, ten per cent, solutions were used, and with turpen- 

 tine a ten per cent, emulsion. In these solutions the seeds were soaked 

 for a period of two or three hours. 



(2) After treatment the seeds were sown in pots containing a sandy 

 loam soil, this in order to determine the effect of the treatment given 

 upon germination. The following table indicates the results of this 

 germination test : 



Deterrent Used. Per Cent, of Germination. 



Check, untreated seed 98-100 per cent. 



Pine tar treatment 98-100 



Coal tar treatment 98-100 



Turpentine emulsion, 3 hrs 38 



Turpentine emulsion. 4)^ hrs 8 



Pyridine solution, 3 hrs 98-100 



Anilin oil solution, 3 hrs o 



