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FARMERS' BULLETIN 797. 



Since the Ames scarifying machine (fig. 8) 1 has been placed on 

 the market, it is possible to buy scarified seed. This machine is so 

 constructed that the seed is forced through a conveyer, part of which 

 is covered with sandpaper. When the seed comes in contact with 

 the sandpaper it is scratched, so that water will penetrate the seed 

 coats. When this machine is run properly the germination of seed 

 is greatly increased, but when carelessly operated germination may 

 be lessened, as many of the seeds may be broken. 



The retarded germination of sweet-clover seed may be overcome 

 by soaking it in commercial concentrated sulphuric acid for 20 

 minutes. It should then be washed quickly, using running water if 



FIG. 8. Ames hulling and scarifying machine. 



possible, as sulphuric acid becomes very hot when mixed with small 

 proportions of water. A great deal of water therefore is necessary 

 in order to lessen the danger of burning. The seed should be dried 

 quickly by spreading it out on a floor or canvas, and it should be 

 stirred at intervals. Unhulled seed should never be treated with 

 sulphuric acid. When only a small quantity of sulphuric acid comes 

 in contact with the hulls a very high temperature will result and 

 the seed will be killed. The treatment of seed with sulphuric acid 



1 This machine was invented by Prof. H. D. Hughes, of the Iowa State College at Ames, 

 A United States patent covering this device has been issued and dedicated to the free 

 use of the public. 



