BRFAKAOF OF F/iflft TN TRANRTT. 



17 



Strength of -fillers. — The strength of various grades of strawboard 

 fillers on the market was accurately measured in compression ma- 

 chines, and, as indicated in Table 6, it varies with their respective 

 weights. 



Table 6. — Crushing strength of fillers. 



Trade name. 



Weight per set. 



Crushing 



strength. 



Strength 

 of tips. 



no.i ....: 



Pounds. 

 3 

 3 

 3 

 2 



Ounces. 

 12 

 6 

 3 

 8 



Pounds. 

 685 

 595 

 471 

 325 



Pounds. 



57 





42 





38 



No. 2 



36 







The strength of the tips of the fillers was obtained by subject- 

 ing them to pressure in a like manner. The close relationship be- 

 tween filler tips and damaged eggs is seen throughout this investiga- 

 tion. It has been observed in field work, and amply proven in the 

 laboratory. For example, the effect of measured blows delivered 

 in a definite way against the end of the case did not wreck the shell 

 of the egg until the tips of the fillers were bent so that the sides of 

 the strawboard cell came in contact with the wood of the case. The 

 tips of the so-called No. 1 fillers were found to protect the eggs on 

 the ends from becoming leakers more effectively than 3-pound or 

 medium fillers, but heavy shocks were observed to cause a light 

 cracking before these heavy tips failed. 



B 



T 



T T T T 



T T 



Fig. 9. — Longitudinal and transverse sections of an egg filler. 



The strips which form the cell Avails of an egg filler are solid (B) 

 on one side and slit (A) on the other (fig. 9) . When the filler is com- 

 pleted, half of the solid sides are upward in the filler, and the other 

 half, running in a transverse direction, are downward. Added safety 

 is gained by placing the upper solid side next to the end and center 

 board of the case, as this prevents the egg from toppling over against 

 the wood. 



