PRINCIPLES OF SEED TESTING 365 



by farmers, for analysis by competent botanists, should 

 if possible be taken in the presence of witnesses. For 

 the farmer's own tests it is sufficient, however, to 

 remove a handful from the centre of each of the several 

 bags purchased, and, after mixing these lots, a small 

 quantity of the mixture may be taken for the test. 



For official samples 2 oz. of the smaller seeds, such 

 as grasses, clovers, turnip, rape, carrot, flax, and parsley, 

 will suffice. Of the larger seeds, such as mangel, sain- 

 foin, hemp, elm, larch, and beech, about 4 oz. samples 

 should be taken ; while of the cereal grains, vetch, peas, 

 beans, acorns, &c., double the latter quantity is required. 



The Purity Test for Farmers. It may be said at once 

 that the average farmer or gardener will only be able to 

 carry out the purity test very roughly, very few being 

 able to recognise the different weed seeds found in the 

 various classes of agricultural seeds. Having obtained 

 a representative sample, however, it should be carefully 

 weighed, after which all the seeds which are true to 

 name should be separated out, for which purpose the 

 sample may be spread on a large sheet of white paper 

 and sorted out with the blade of a pocket-knife. This 

 being done, the balance, consisting of dust, rubbish, and 

 weed seeds is the impurity. A further weighing will 

 give its amount, when the percentage of pure seed may 

 be calculated. For ascertaining the purity a small 

 chemical or spring balance will be necessary in order 

 that accurate weighings may be made. The ordinary 

 " purity " of many seeds is given at p. 371. 



The Germinating Test for Farmers. Having re- 

 moved the rubbish, weed seeds, and other impurities 

 from the sample, and ascertained the purity, 200 to 

 400 of the pure seeds are now taken and separated 

 into two equal lots. Each of these lots of 100 or 200 

 is then placed between a folded piece of damp blotting- 



