COVERING THE SILOED FODDER. 161 



gas is evolved, and if the silo is shut up tight the gas will 

 gradually accumulate directly above the fodder, since it 

 is heavier than air and does not mix with it under the con- 

 ditions given. If a man or an animal goes down into this 

 atmosphere, there is great danger of asphyxiation, as is 

 the case under similar conditions in a deep cistern or well. 

 Poisoning cases from this cause have occurred in filling 

 silos where the filling has been interrupted for one or more 

 days, and men have then gone into the silo to tramp down 

 the cut corn. If the doors above the siloed mass are left 

 open when the filling is stopped, and the silo thus venti- 

 lated, carbonic acid poisoning cannot take place, since the 

 gas will then slowly diffuse into the air. Carbonic acid 

 being without odor or color, to all appearances like ordi- 

 nary air, it cannot be directly observed, but may be readily 

 detected by means of a lighted lantern or candle. If the 

 light goes out when lowered into the silo there is an 

 accumulation of carbonic acid in it, and a person should 

 open feed doors and fan the air in the silo before going 

 down into it. 



After the silage is made and the temperature in the 

 silo has gone down considerably, there is no further evo- 

 lution of carbonic acid, and therefore no danger in enter- 

 ing the silo even if this has been shut up tight. The 

 maximum evolution of carbonic acid, and consequently the 

 danger of carbonic-acid poisoning comes during or directly 

 after the filling of the silo. 



Covering the Siloed Fodder. 



Many devices for covering the siloed fodder have been 

 recommended and tried, with varying success. The orig- 

 inal method- was to put boards on top of the fodder, and 

 to weight them heavily by means of a foot layer of dirt 

 or sand, or with stone. The weighting having later on 

 been done away with, lighter material, as straw, hay, 

 sawdust, etc., was substituted for the stone o^'.sand.' 

 Building paper was often placed over the fodder, and 

 boards on top of the paper. There is no special advan- 



11 - * ' 



