CONDUITS, POKTAGE, ETC. 293 



ing or repairing them. It was for these reasons that I first used flexile 

 systems of tubes and cheap apparatuses to be tested. When they trail 

 upon the ground they are not afiected by its irregularities, nor do they 

 catch upon the plants to receive or give injury, but conform easily to 

 all changes of the ground or the rows. In turning in the cotton the 

 hanging flexile forks drag through among the plants, and when the ap- 

 paratus is turned short on only two wheels so that one of its sides 

 swings somewhat backwards while the other goes around, or when the 

 machine is backed by any accidental or intentional movement of the 

 horses in the cotton, the forks are not pushed into or against the plants 

 in the injurious manner which might result were the stem and branch 

 pipes entirely stiff ; but in such cases the pliable pipes bend while the 

 lower part of the fork does not move or else is dragged backward with 

 no possible harm. But in order that the wheels in turning do not run 

 onto the fork-arms if lying on the ground, these must be suspended 

 from safe points either before or behind the wheel, or at such a distance 

 to one side from the wheel that it cannot be turned forward or backward 

 to roll u])on the arms. The peculiar disposition of the parts in the A- 

 frame machines shown in the jiiates is such as to insure safety in these 

 respects. It should also be added that block-tin pipes and copper or 

 lead tubes are valuable on account of their being less subject to corrosion, 

 but the softness or pliability of these metals allows such tubes to bend 

 easily, hence, where employed, they should be attached at short in- 

 tervals upon some rigid support or have a stiff internal rod such as I 

 have introduced in hose to maintain it in such direction, course, or po- 

 sition as may be wished. Zinc does not rust, but is most easily cor- 

 roded by anything of an acid nature. It will generally be preferred to 

 common tin, but is somewhat softer and breaks more easily. Such pipe 

 systems can be used with any kind of poison receptacle or with any 

 forcing medium, such as a force-pump, bellows, gas-pressure generator, 

 or a gravitating column of liquid. 



For pipe-systems of stiff', flexible, or flexible-jointed tubing, embrac- 

 ing forks of the kinds just described, to be carried or trailed through 

 the field, I have combined groups of various sizes, including two or 

 more of the forks, and some different means of support and conveyance 

 of the same need to be considered here. The old-fashioned way of giv- 

 ing support to the i)rimary or main trunk-branches of tubes by attach- 

 ing them to the rear horizontal i^arts of any suitable vehicle, to some 

 frame, bar, or box upon the same, is naturally the simplest; but adjust- 

 ability to suit row-spaces of different widths is desired, and different ar- 

 rangements withthese should be adopted. As illustrating this topic the 

 following machine should be noticed. This machine was planned by me 

 and tested to show a possible adjustability and the possible width that 

 might be embraced in one of these machines. Plate XLYII exhibits a 

 rear view of this apparatus as cut from a photograph of it taken to 

 show its operation in the field. The cotton being unusually small and 



