10 



BULLETIN 664. V. S. DEPARTMENT OF A.GRICULTTTHE. 



is. however, a distinct difference, approximately 1.1 per cent, between 

 the sound and the unsound eggs. This figure, applied to case lots of 

 unsound eggs, shows an additional damage having a commercial im- 

 portance. Applied, however, to the case of rchandled eggs as com- 

 monly pul up by the shipper, containing L9 with unsound shells, it 

 amounts to only 0.2 egg per case, a negligible number. Apparently, 

 then, the matter of the 19 cracked eggs, as found in the well packed 

 standard package, becomes an economic question of keeping quality 

 in cold storage and of marketing, not of transportation damage. 



THE CHARACTEB OF THE PACKAGE. 



strength of cases. — In the course of this investigation the standard 

 Qgg package was subjected to various tests 1 to determine the relative 

 strength of the three kinds of wood (gum, tnpelo, and cottonwood) 

 commonly used, the number of nails needed, the manner in which the 

 cases failed when subjected to evenly exerted pressures, and to obtain 

 other data bearing on the subject. A summary of results, the details 

 of which are too lengthy to be included here, is presented in this 

 bulletin. Table 5 gives the average number of pounds of evenly 

 applied pressure which the different cases withstood before they 

 failed or became crushed. 





•Table 5 — 



Analysis 



of strength 



of egg 



cases. 









Material. 



Type. 



Strength. 







Diagonal. 



Length- 

 wise. 



Side- 

 wise. 



Vertical. 



Weight. 







Pounds. 

 590 

 567 

 687 



Pounds. 

 2,214 

 2,110 



1,914 



Pounds. 

 9,810 

 13, 629 

 12, 143 



Pounds. 

 20, 343 

 21,257 

 20, 294 



Pounds. 

 7.25 





....do 



8.89 



Tupelo 



....do 



8.24 









In spite of greater weight, the gum and tupelo cases offer no addi- 

 tional strength as compared with cottonwood. On the other hand, 

 cottonwood presents certain advantages in that it is softer and 

 odorless, and does not warp or crack as readily as the other woods. 

 The results given in Table 5 are based on cases made up with 5 

 cement-coated 3-penny nails at each corner of the sides and bot- 

 tom and at the center partition. If only 4 cement-coated nails are 

 \i<c(] the package is weakened: this was also the case with smooth 

 nails, even when 5 were used. The use of 6 cement-coated 3-penny 

 nails slightly increases the rigidity of the case, an important fea- 

 ture in safe transportation, since distortion of the case soon causes 

 breakage. The same added rigidity is noticed when wire binding 

 is used around the sides and bottom of the case at the ends; likewise 

 when the lid is nailed in the center. 



1 The tests were made in cooperation with the Forest Products Laboratory, of the U. S. 

 Department of Agriculture, and the Bureau of Standards, of the U. S. Department of 



Commerce. 



