ENSILAGE AND FERMENTATION. 221 



The next step in advance, which quite naturally followed, was, to sub- 

 stitute a movable cover of boards, with weights to give the required 

 pressure, for the cover of earth which had been used in the less perfect 

 form of the silo. As an air-tight inclosure was found to be the essen- 

 tial condition in the construction of a silo, lighter walls were made as 

 a matter of economy, with good results, and even frames of timber, 

 lined with boards or planks, were substituted for the more expensive 

 structures, with complete success. 



A balloon-frame of scantling, of suitable size, covered on the out- 

 side with matched boards, and lined on the inside with two thick- 

 nesses of one-inch matched boards, with a layer of tarred paper between 

 them, thus securing a practically air-tight inclosure surrounded by a 

 dead-air space as a protection against frost, is, in the opinion of the 

 writer, the best and cheapest form of construction. If the boards and 

 timbers are saturated with hot coal-tar, which can readily be done 

 with trifling expense, the durability of the silo will be very much in- 

 creased. From the fact that wood is not so good a conductor of heat 

 as walls of masonry, it will be seen, from what follows, that wooden 

 silos may have an important advantage over any others in preserving 

 the ensilage, which, in connection with the saving of expense in their 

 construction, must have an influence in bringing them into general use. 



There are many conflicting statements in regard to the value of 

 ensilage as a cattle-food, and it may be that the failure to realize the 

 exaggerated claims that were made for it when, first introduced has 

 resulted in a reaction which naturally leads to a low estimate of its 

 value. It must, however, be admitted that a large proportion of the 

 farmers who have used it are fully satisfied that it is a desirable and 

 valuable form of cattle-food, and many would not limit its use to the 

 winter months. Others speak with less confidence of the results of 

 their experience, and are inclined to admit, with those who are not con- 

 vinced of the utility of the process, that the acidity which is devel- 

 oped to a greater or less extent, in most cases, is decidedly objection- 

 able. Experience at the condensed-milk factories is claimed to be 

 unfavorable to ensilage as food for cows, and some of them refuse to 

 receive milk from farms where it is fed. 



That there are great differences in the quality of the ensilage made 

 on different farms, or even in that made on the same farm in different 

 seasons, there can be no doubt, and these differences must be attributed 

 to variations in the conditions under which the ensilage is made, which 

 must fesult in corresponding modifications of the process of fermenta- 

 tion. When the influence of these varying conditions, which include 

 the peculiarities of the crop, as well as the method of filling the silo, 

 is so well understood that ensilage of a uniform and desired quality 

 can be produced with certainty, the most important objections that 

 are now made to it will be obviated, and it will readily take its place 

 on the farm as a staple article of cattle-food. 



