OSWALD] SEED TESTING 15 



Fig. 4. Tripod Lens and Forceps Used ix Making Purity 



Tests. 



or power of germination. In order, therefore, to get a correct 

 knowledge of seed to be planted both purity and germination 

 tests are necessary. 



It will be the object of this paper to show how both purity 

 and germination tests can be made in schools or at home with- 

 out the use of expensive apparatus, — a Nature study lesson at 

 once interesting, instructive and practically profitable. In mak- 

 ing a purity test one needs to have a knowledge of the different 

 weed seeds. The best way to recognize weed seeds is to have 

 samples of them with which to compare the unknown seeds. 

 These seed samples may be collected by the students and then 

 with the aid of the instructor correctly named and labelled. 

 Samples may also be obtained in sets from Experiment Sta- 

 tion and from the Seed Laboratory at Washington, D. C. A 

 convenient form of seed case is shown in the accompaning figure. 

 On account of the fact that a collection is so essential in this 

 work and since the case figured is so easily prepared a descrip- 

 tion of its manufacture will be given. 



This seed case has been devised at the Minnesota Agricul- 

 tural Experiment Station. It can be easily and cheaply dup- 

 licated by the average student, as it is very simple in construc- 

 tion. It requires two pieces of glass, one piece of fairly thick 

 card board and one of white bristol board, all 5xT inches in 

 size. Twenty-four holes or pockets are cut in the cardboard. 

 These can be easily cut with a No. 12 gun-wad punch, or can 

 even be made with an ordinary brace and bit. using a ^-inch 

 bit. The holes should be bored only half through the card- 



