53 



shown no deterioration after two years' constant use. In those 

 used by me there has been no indication of the front flap breaking 

 at the hinge, and should it eventually break it can be very easily 

 repaired with gummed cloth or craft tape. In arranging the 

 boxes in single or double tiers, the individual units may be 

 pasted in place with sodium silicate (water glass) or the upper 

 and outer rows may be merely bound in place with craft tape. 

 The former method is best, as thoroughly pasting the bottom 

 of one unit on the top of the one next below is structurally 

 stronger and tends to prevent sagging. The individual units 

 may be stacked in double rows, back to back, forming alcoves 

 and the containers are so strong that they may be stacked to 

 any reasonable height. The stacks at present in use are about 

 six feet high. 



In these days of high costs, the economy ot this type of 

 herbarium case is most striking. On the basis of orders of five 

 hundred units delivered "knocked down" and ready to put 

 together, the cost in San Francisco is about fifteen cents each. 

 At a cost of about Si 50.00 storage space for approximately 



