1912] Goodspeed: Nicotiana Hybrids 93 



the seed could be poured in and neither be driven back up the 

 tin funnel by the air-current nor fall back down the tube into 

 the pan, was determined by experiment, as was also the proper 

 angle at which the tube should be tilted to give the necessary 

 "throw" to the seed after it left the upper end. A large paper 

 shield, reaching to the table, was fastened two inches back of 

 the upper end of the tube and thus effectuall}- excluded any 

 current of air in the region through which the seed fell and 

 about the receiving boxes. These boxes, • eight of them and 

 placed end to end, extended for three feet from a point directly 

 below the outlet of the tube. A box with high, sharply sloping 

 sides, partially closed at the extreme end and open above the 

 receiving boxes, extended the full length of the boxes to catch 

 any scattering seed and direct it downward. The maximum drop 

 of the seed into the boxes from the mouth of the tube or during 

 its progress through the air above the boxes, was about twenty 

 inches, though by far the majority of the seed began to fall, to 

 some extent, as soon as it was free from the tube. 



After considerable effort had been expended in perfecting 

 the arrangements and determining by direct experiment the 

 proper position for the receiving boxes, etc., it was possible 

 to accomplish the entire grading of the seed on two successive 

 days during approximately the same hours. Since a motor at- 

 tachment was not available, it was not possible to regulate the 

 speed of the fan exactly and thus secure a perfectly constant 

 blast of air for any length of time. But by using the apparatus 

 on two successive days and at the same hours, it was judged 

 and proven by actual test that the blast was approximately the 

 same during the whole time of grading the seed. 



The seed was slowly poured into the funnel directly from 

 the packet into w^hich it had been cleaned until perhaps a 

 thousand seeds had fallen into the receiving boxes. This first 

 grading was always very rough and gave only an approximate 

 separation according to density. Contrary to expectation, it 

 was found that the heaviest seed continually fell in the boxes 

 furthest from the opening of the tube, while the lightest and 

 medium seed fell into the first five boxes. The ill-formed, chaffy 

 seed was distributed throughout the whole of the eight boxes. 



