SEEDS AND SOWING. 159 



tween boards. This also has for advantage the sepa- 

 rating of the same, as ah'eady stated ; several adhere to 

 each other, the inconvenience of which-? in sowing by 

 machiner}^^ is great. A certain amount of humidity 

 being necessary before germination commences, if we 

 can give this before placing the seed in the soil it will 

 evidently represent so much time gained, and for that 

 reason the placing of the seeds a certain number of 

 hours in water has been sug^o^ested. If for too long: 

 a period much harm will be done, as the seed will be 

 greatly weakened* if too much water has been absorbed. 

 There is then great danger of a rapid evaporation, which 

 will thus leave the seed dryer than before, and for that 

 reason it has been proposed to add to the water an 

 equal volume of urine, and to place the seed in the 

 same for about forty-eight hours, then put them in 

 piles a few inches in height. An elevation of tempera- 

 ture will follow, which will consequently represent a 

 gain in heat, as there can be no doubt a given number 

 of degrees are necessary, this is suj^posed to be 248^ 

 to 260° F.' 



' See " Sowing." 



* The importance of these elements has already been explained. By boil- 

 ing the resulting liquid we have a test ; if ammoniacal gases are detected in 

 considerable quantities it gives an almost positive proof that the maceration 

 has lasted too long, and that the discoloration is not due to an old seed. 



* If we suppose that the temperature for several days had been constant, 



2660 — 32=' 

 ,00° F., for example, it would require . q ^7^^ 13 days before the germi- 



