7(i-2 JUSKINC .\M> < |.i;AMN(i (ONIFEItoUS SEEDS. 



placed on the trays. Alter the heat has been applied and the 

 cones bcfjin to steam, all vent-holes must be opened. As soon 

 as the air becomes drier and the cones have been exposed for 

 some time to the heat, they begin to open. This does not 

 jjenerally happen simultaneously on all the trays ; the current 

 of hot air is then turned in the direction of the backward trays 

 l»y opening certain vent-holes, or changing the places of those 

 trays with those where the cones have opened and thus exposing 

 them to the hottest blast. 



Management of the heat is the most important point in the 

 kilns. The heat should rise as uniformly and quickly as possible 

 to the temperature most suitable for the apparatus and cone in 

 question. Scotch pine cones require the greatesi heat, usually 

 100-112- F. ; spruce, 90-100"-" F. ; Weymoutli-pine and alder, 

 ()G' -77^ F. If the apparatus works so well that the seed falls 

 straightway from the cones on to the cool floor and is then 

 i-emoved as soon as possible, higher degrees of heat are admis- 

 sible ; thus in the case of Scotch pine cones, temperatures of 

 140^^-145'^ may be attained without impairing the germinating 

 power of the seeds, provided that the high temperature is at 

 once reduced to 110° or 120°, as soon as the cones begin opening 

 and this temperature maintained until the end of the operation. 

 In many places, a temperature of 160° is applied, but this is 

 permissible only in the drum process, where the workman is not 

 obliged to turn over the cones inside the kiln, which would be 

 impossible at such a temperature. 



As empty cones are generally used for fuel and give out heat 

 quickly, a few cones should be added to the fire every 15 minutes 

 or so. The stoker must attend carefully to the direction of the 

 wind, &c., and endeavour as much as possible to supply the 

 requisite amount of heat. 



The time required to opi-n the cones thorouglily depends on 

 several conditions. First, the species of cone ; Scotch pine cones 

 require the highest temperature, whilst cones of other species 

 open more readily. Cones open more readily when collected 

 after November ; frost has a considerable effect on the opening 

 of the cones ; thus, in mild winters with little frost, the business 

 of seed-kilns is considerably delayed ; cones open more freely 

 when they are brought damp and cold from the store-room into 



