26 BULLETIN 664, U. S. DEPARTMENT OF AGRICULTURE. 
(p. 7) at the other. The results are shown in figure 12, which indi- 
cates that 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 16 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. Nailed 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. 
