THIRTY-FIFTH ANNUAL CONVENTION. 289 



building tile for silo walls. For several years, tile has been used 

 with the best of success for the construction of fireproof grain 

 storage tanks. The advantages of building tile for silo con- 

 struction are many. The nature of the work is thoroughly 

 familiar to bricklayers and masons in every locality and a satis- 

 factory job is practically assured. Every feature of the design, 

 by its application to a similar use, has proven its practicability. 

 Owing to the fact that tile itself is splendid non-conductor of 

 heat and that the circulation of air in the hollo W wall is so well 

 restricted, perhaps no silo can provide better protection against 

 freezing. In addition, the construction is as fire proof as any 

 masonry construction. 



The material used in the Iowa silo as originally designed 

 was rectangular, hollow, clay building blocks, such as have been 

 commonly used extensively in important buildings for years. 

 Furthermore, it was designed with a plaster coat of cement mor- 

 tar both inside and outside. The experimental silo was not 

 plastered, simply washed inside with a cement wash and for the 

 year it has been in use it has been entirely satisfactory, indicat- 

 ing that plastering is not necessary where a tile block is used 

 which will resist the weather. It is to be noted that the dura- 

 bility of this type of silo will depend upon the quality of the 

 tile, which varies widely. Soft tile which have not been properly 

 burned should be guarded against. On the other hand, good 

 vitrified blocks are among the most reliable and durable of all 

 building materials. Special blocks bent to the curvative of the 

 silo may be purchased from several manufacturers in the state. 

 Ten or more silos have been built of these curved blocks during 

 the past summer and a full account of the success of these silos 

 will be published later. 



The previous discussion of foundations applies in general 

 to this class of silos, but circumstances may arise where it may 

 be desirable to use tile beneath the ground. It has not been 

 fully demonstrated that any clay product but a hard burned 

 vitrified tile or brick will withstand such use. The tile in the foun- 

 dation are stood on end and filled with concrete. Outside of the 



