524 Forestry Quarterly. 



really effective the intensity must be such as is needed for com- 

 fortable reading; beyond this, the intensity has hardly any in- 

 fluence. No difference is observed, if the desired intensity is 

 used, between natural and artificial light, which latter is com- 

 mendable in scientific investigations and large seed-testing estab- 

 lishments. 



For seed tests under natural light, rooms looking north are 

 desirable ; on no account should there be a direct sunlight strike 

 the tests, since that excludes control of temperature; glass-covered 

 hothouses are therefore also not desirable for finer tests. 



5. Pure air is to be continuously had in the test laboratory. 



6. The progress of germination (number of seeds germinated 

 per day) of any seed under continuously equal conditions is rep- 

 resented in a curve whose last end is precisely indicated by the 

 front end, which after long enough observation of the beginning 

 of the curves can with certainty be mechanically drawn (a large 

 number of curves are represented). The best most expressive 

 form of a seed test certificate is the germination curve; it gives 

 an absolutely clear picture of seed quality, such as a common 10 

 or 20 day germination per cent, secured under varying tempera- 

 ture conditions cannot give. 



Where briefly a judgment is to be given, the rapidity of germi- 

 nation is better expressed by the time it took under the stated 

 temperature to bring half the germinative seed to the germination, 



(25°) 

 instead of the usual lo-day statement: E. g " "^ 



5-8 



seed, which in 25° C took 5.8 days to bring 42 seeds to germina- 

 tion. Usually 12 days will suffice for this purpose. Most simply 

 the curve of these 12 days gives the information. 



7. The germinative energy of useable pine seed, if determined 

 by a sufficient number of seeds can even in simple test laboratories 

 be determined with such certainty as is possible within the theory 

 of probable error. 



Die Priifung des Kiefernsamens. Zeitschrift fur Forst-u. Jagdwesen, 

 April-May, 19 12. Pp. 193-222, 273-307. 



