720 IOWA DEPARTMENT OF AGRICULTURE 



EASE OF MAKING PRACTICAL TESTS. 



Seed tests sufficiently accurate to answer all practical purposes can 

 be made by a beginner with a little practice. Certain time-consuming 

 and exacting features of detail in making official tests at Washington or 

 at an experiment station are often unnecessary in making tests for the 

 facts of most practical importance. 



By providing the apparatus and following the directions for making 

 tests suggested in the following pages and by using the illustrations 

 in comparing seeds of different kinds one can soon become sufficiently 

 expert to feel reasonable confidence in his ability to avoid errors of 

 importance. 



The younger members of the home circle should find such work com- 

 paratively easy to accomplish and interesting as well. The testing of 

 locally grown seed would be assisted by the possession of a correctly 

 named set of the seeds of crops and of weeds prevailing in the vicinity. 



When the work is done in the school, samples of seed of local inter- 

 est and obtainable at the homes of the pupils may be used. This tends 

 to impress the pupils (and their parents as well) with the immediate 

 utility of the work. If suitable seed is not obtainable locally, samples 

 representing different grades can be obtained from dealers. The boys 

 can make the balance here described. Several balances may be made 

 and their efficiency compared. The successful making of such apparatus 

 has a distinct educational value of its own. One pupil may be authorized 

 to procure the magnifiers required; another may be delegated to provide 

 one or more plate germinators or to make the corn-germinating box. 

 Germination tests made in cloth, paper, sand, and soil may be compared, 

 showing the effect of surrounding conditions. Such actual practice makes 

 the pupil do and think and fits him to master corresponding but more 

 complex problems later. 



APPARATUS USED IX MAKING TESTS. 



The Need of Apparatus — Only such apparatus is needed in making 

 practical seed tests as enables one to use a weighed quantity of seed 

 from the sample, to separate the pure seed from the foreign seeds and 

 other impurities, to distinguish the character of the foreign seeds, and 

 to make the germination test. 



It is important to use a weighed quantity of seed in the test, because 

 only in this way can one determine the relative quantity or percentage 

 of pure seed as compared with the quantity of the impurities. This 

 requires a balance sufficiently sensitive to be moved by a small weight, 

 such as that of a few clover seeds. The sensitiveness is necessary, be- 

 cause only a small sample of seed can be used in the test. A large 

 sample would require too much time and labor. For this reason only 

 small samples are used in making official tests of seeds. 



The absence heretofore of a readily available, effective balance suited 

 to this work, doubtless has been the chief bar to the popularizing of 

 farm and rural-school seet testing. Expensive chemical balances are 



