20 BULLETIN 664, r. S. DEPARTMENT OF A< iKUT I.TURE. 



(p. 7) at the other. The results are shown in figure 12, which indi- 

 cates thai approximately 50 per cent of the refrigeration available 

 is lost by buffing solidly to the floor. During the early spring, when 

 the weather is cool, this loss of refrigeration is not serious. When 

 shipments are made in warm weather, however, it is a question which 

 must be considered. The straw buffing, properly applied, may save 

 damage to the shell of an egg or two per case, but if it permits of 

 unchecked deterioration from heat it is of very doubtful economic 

 value. Under warm weather conditions the shipper should consider 

 the relative advantages of the small frame described in this report 

 or of wood buffing. 



If the load is to be a solid unit in the car, the form of brace to be 

 used, in case the layers are not complete throughout, becomes an 

 important matter. The mere weight of the cases in an incomplete 

 top layer is not sufficient to keep them in place. In 1G of 36 such 

 loads traced to the market serious damage occurred. Failure to 

 brace an incomplete top layer, especially in mixed cars, is a frequent 

 source of serious damage. A roaming case is not only damaged 

 itself, but it damages other cases. The scantling braces nailed to 

 the walls of the car seldom arrive in place. They should never be 

 used. The most satisfactory braces found up to the present time are 

 those described on page 8. It is readily seen that, if the load is to 

 be a solid unit inside the car, the braces must be a part of the load 

 itself, and must in no wise depend upon the car for resistance or 

 strength. Xailed braces are a part of the car, not a part of the load. 



THE CONSTRUCTION OF THE CAR. 



Observations during yard shifting showed that freight cars hav- 

 ing steel underframe construction do not react to shocks in the same 

 way as do those having wooden underframes. Cars with wooden 

 underframes give under impacts in such wise that the load receives 

 less of a jolt than that in the steel-framed car. There is a slight in- 

 crease in damage to eggshells when carried in steel underframe cars, 

 all other conditions being equal, as shown in Table 13. This tendency 

 is visible whether the load is buffed with wood or straw, or whether 

 well or poorly stowed. 



