146 Colcord's System of 



when removed from the silo, piled in a heap 

 and left exposed to the air, as ensilage does. 



The silo being sealed up air-tight, all the gas 

 coming from it had to come out through the 

 governors at the top of the silo. The next 

 morning after commencing to fill, carbonic 

 acid was abundant. The second day, we had 

 acetic acid, with no rise of temperature. These 

 two acids appeared to be all that came out of 

 the silo. They were very pure and odorless. 

 It is fair to presume that, as carbonic acid is 

 heavier than air, and was present in quantity, 

 it displaced the air in the silo, and that, being 

 readily absorbed by the water or juice, it had 

 a tendency to form a vacuum, which, com- 

 bined with the pressure and capillary attrac- 

 tion, brought the juice to the very top plank. 

 The silo is now just half empty. The perpen- 

 dicular face of the cut is 13^ feet. From any 

 part of this face, we can take a handful of the 

 corn and squeeze the juice from it with one 

 hand. The lower half of this mass occupies 

 less than half the space it did when put in. 

 The upper half shows much less pressure ; but 

 the weight of a cubic foot of each is about the 

 same, showing the proportion of juice to corn 

 is much greater in the top half. Heavy press- 

 ure was kept on for six weeks. During all this 

 time, acetic acid came out pure and pungent. 



