194 CHYMISTRY APPLIED TO AGRICULTURE. 



carbonic acid, (as I have explained in speaking of the 

 action of air upon fruits,) and the insects will remain tor- 

 pid. This last assertion is, as we shall shortly see, sup- 

 ported by the results of the experiments which have been 

 made by the Board of Provisions of War, for the purpose of 

 ascertaining the best mode of preserving grain. 



But the construction of these trenches, as it involves 

 some expense, and requires much care, will be for a long 

 time rejected by mere farmers. However advantageous 

 this arrangement may be, it belongs entirely to public au- 

 thorities, great cities, and governments, to set an example 

 of the use of it, by withdrawing from circulation, during 

 years of abundant harvests, large quantities of corn to be 

 deposited in trenches and preserved against years of scarci- 

 ty. Much has been written, within a few years, upon the 

 best methods of preserving grain ; but all those that have 

 been proposed were founded upon the same principles. 



The Board of Provisions of War, under the direction of 

 Count Dejean, has performed a series of well-directed ex- 

 periments, from which excellent results have been obtain- 

 ed : the apparatus used in them consisted of lead receivers 

 hermetically sealed and having all their joinings soldered. 

 Meal and grain full of weevils were enclosed in three re- 

 ceivers ; when these were opened, at the end of a year, it 

 was found that no injury had been done by the weevils ; 

 they were all either dead or in a state of torpor. In one 

 of the receivers there was found a collection of grains ad- 

 hering to each other in a mass about as large as a mid- 

 dling-sized apple : this arose from the entrance of air and 

 moisture through a hole the size of a pin, accidentally left 

 unsoldered in one of the joints. 



The elder M. Ternaux caused trenches to be formed 

 and filled with corn in the beautiful field of Saint Arven ; 

 in order to be sure of the preservation of the grain, he 

 caused the trenches to be opened from year to year, and the 

 results were always satisfactory. 



Corn, well dried and guarded from air and moisture, 

 may be preserved in the ear for a long time, and it is a 

 well-known fact that in some agricultural countries the 

 sheaves are formed into stacks which are taken down 

 either for consumption or the market, at those times when 

 the laborers upon the farm can be employed only in thresh- 

 ing in a barn. 



Instead of constructing trenches of stone without the 



