98 THE BOOK OF ALFALFA 



From the fact that spontaneous combustion cannot 

 take place until the water has all been evaporated, there 

 is no danger until three to four weeks after the hay has 

 been stored. During the first week or so, if the hay 

 heats to such an extent that there is danger of com- 

 bustion, it is well to open up the center as much as pos- 

 sible and allow some of the heat to escape. If, however, 

 the heating has continued much longer, it is dangerous 

 practice to open the hay at all, because all that is needed, 

 after the water has been evaporated, is air, or oxygen to 

 support combustion, and the mass will at once burst into 

 flames. Sometimes combustion takes place without 

 flames, in which case the center of the mow gradually 

 chars, leaving the hay there as black as charcoal, and 

 without value. 



Professor Cottrell, discussing spontaneous combustion 

 (Kansas Bui. No. 114), says that all cases observed by 

 him have occurred in hay of the season^s first cutting — ' 

 cut at a time when the growth was rank and the curing 

 most difficult A period of wet, muggy weather in July 

 or August increases the danger, which in dry weather 

 seems much less. On accoimt of previous trouble from 

 heating in the barn, he had four years prior to writing 

 stacked the first cutting out of doors and put only the 

 later cuttings in the barn. 



LOSSES ITROM STAOKIlSrG. 



The Colorado station found that the loss in feeding 

 value from the hour of cocking to the hour of taking from 

 the stack was 12.4 per cent, while the loss in hay stored in 

 the barn was but 2.5 per cent. If we add to this the 

 stacked hay lost by exposure, it will easily reach more than 



