4 N. H. EXPERIMENT STATION [Bulletin ISO 



tories of the country, and which seems to afford a very satis- 

 factory method of allowing or tolerating a reasonable varia- 

 tion in purity tests. The percentage variation for any given 

 sanii^le is determined by the following formula : 



^ 2(.1+100— P) 



10 



in which "T" is the variation tolerated and "P" is the per- 

 centage of purity found. This formula applies only to seed 

 having a purity of 50% or greater. 



After applying the variations found by the above formula 

 to the results of our tests we have simply used the following 

 terms instead of stating the actual figures in the tabulations : 



"Satisfactory," meaning that the difference between our test 

 and the guarantee is within the variation allowed; "Above," 

 meaning that our test, after allowing for the variation, is above 

 the guarantee; "Below," meaning that our test, after allowing 

 for the variation, is below the guarantee. 



In the matter of germination a variation of 5% has been al- 

 lowed in the statement of results and the same terms used as 

 described above for purity. 



The writer desires to acknowledge his appreciation of the 

 careful and efficient work of Mr. Herbert R. Runnals, who as- 

 sisted in making the tests and examinations of the samples 

 herewith reported. 



