12 BULLETIN 35, U. S. DEPARTMENT OF AGRICULTURE. 



saws, and as soon as there is sufficient demand these firms will be pre- 

 pared to furnish large quantities of properly prepared material at 

 prices which will render possible its use for commercial grape 

 packing. 



The fine particles can be easily separated from the coarse material 

 by passing the dry sawdust through a revolving cylindrical sieve. 

 A type of cleaning apparatus devised in the grape-storage investi- 

 gations of the Bureau of Plant Industry consists of two cylindrical 

 sieves from 6 to 10 feet long, mounted on a continuous shaft in an 

 inclined position, the sieves being made of strong 6-mesh and 14-mesh 

 wire screen. Sawdust of the proper grade is obtained by sifting 

 the fine dust through the 14-mesh screen, while the coarse particles 

 are carried over on the 6-mesh screen. Instead of using two sep- 

 arate cylindrical screens mounted on a continuous shaft, much space 

 may be saved by having the wider mesh screen inclosed within a 

 larger one of the 14-mesh size, the double cylinder revolving on an 

 inclined shaft. The crude sawdust is emptied into the inner screen, 

 which removes the coarse chips and splinters, allowing the residue to 

 drop through into the outer, finer mesh cylinder. This screen in 

 turn allows the objectionable small slivers and dust to sift through, 

 while the desirable material is carried to the end of the cylinder and 

 either emptied into a receiving bin or run directly into sacks. When 

 packed in this material the grapes can be freed from the sawdust 

 by slightly shaking the bunches on removal from the package. 



During the season of 1911 one of the large redwood-lumber milling 

 companies in California cooperated with the Bureau of Plant In- 

 dustry in devising a practicable method of drying and cleaning the 

 sawdust on a commercial scale. The successful outcome of this 

 work enabled the company to furnish to some of the grape growers 

 enough sawdust to pack several carloads of grapes, the cost of this 

 material averaging about 14 cents per drum. It is believed, however, 

 that with the construction of special machinery for drying and 

 cleaning the sawdust, large quantities can be handled easily and 

 quickly and the cost of preparation considerably reduced. 



THE GRAPE DRUM OR BARREL. 



A small barrel or drum has thus far been found to be the most 

 acceptable container for grapes packed in sawdust. These drums 

 are made of thin veneered cottonwood, lined with heavy strawboard. 

 The drum used during the season of 1911 was about 12 inches in 

 diameter, 17 inches in height, and had a net capacity of 27 pounds 

 of grapes, the empty drum weighing about 5|- pounds and the filler 

 about 9 pounds. A drum of larger size (Pis. VII and VIII) suitable 

 for commercial shipments has now been adopted by some of the 

 grape growers and shippers who wish to establish a package of stand- 



